There are many activities you can do in the caves below, which offer their own brand of underground magic; each cave is like a different world—some feel like fantasy novels, others like sci-fi movies.
Son Doong Cave, Vietnam
Multi-day expedition: Trek through dense jungle, cross rivers, and camp inside the cave.
Explore underground jungles and skylights where sunlight streams in.
Climb the “Great Wall of Vietnam”, a 90-meter calcite wall at the end of the cave.
Mammoth Cave, Kentucky, USA
Ranger-led cave tours: From easy strolls to lantern-lit adventures.
Hiking, biking, and horseback riding on over 80 miles of surface trails.
Kayaking and canoeing on the Green and Nolin Rivers.
Clearwater Cave, Malaysia
Boat rides through subterranean rivers.
Walk along plankwalks and floating bridges inside the cave.
Swim in a crystal-clear pool at the cave’s mouth.
Visit Wind Cave nearby, known for its breezy passages and stunning formations.
Postojna Cave, Slovenia
Ride an underground train through the cave’s vast chambers.
Walk among stalactites and stalagmites in the “Concert Hall.”
Visit the Vivarium to see olms—rare cave-dwelling amphibians.
Explore Predjama Castle, built into a cliff above a cave.
Waitomo Glowworm Caves, New Zealand
Boat ride under a galaxy of glowworms—a surreal, silent experience.
Guided walking tours through limestone formations.
Adventure caving and black water rafting in nearby Ruakuri Cave.
Fingal’s Cave, Scotland
Boat tours to the uninhabited Isle of Staffa.
Walk into the cave along natural basalt columns (tide permitting).
Marvel at the acoustics that inspired Mendelssohn’s “Hebrides Overture”.
Son Doong Cave, Mammoth Cave, Clearwater Cave System, Postojna Cave, Waitomo Glowworm Caves, Fingal’s Cave, Lechuguilla Cave, Shuanghedong Cave Network, Ox Bel Ha System, Mulu Caves, and Blue Grotto are some of the largest and safest
caves around the world that welcome curious explorers; each of these caves offers a unique experience, from natural wonders to cultural history.
Son Doong Cave (Hang Sơn Đoòng), Vietnam - The largest cave in the world by volume, Son Doong with 38.5 million cubic meters of volume is a surreal landscape with its own jungle and weather system.
Located in Phong Nha-Ke Bang National Park, it’s accessible via guided expeditions that prioritize safety and conservation, it's also considered safe for exploration with proper guidance and equipment, and so large
that it could fit a 40-story skyscraper or a Boeing 747 inside.
Mammoth Cave, Kentucky, USA - Among the world’s most visited and tourist-friendly caves, Mammoth Cave in Kentucky, USA stands out as a top contender. It’s the longest known cave system on Earth, with over 420 miles of mapped passages,
and it draws hundreds of thousands of visitors each year thanks to its well-developed infrastructure, diverse tour options, and rich history. It’s a UNESCO World Heritage Site and offers well-maintained walking tours for all levels of
adventurers.
Clearwater Cave System, Malaysia Found in Gunung Mulu National Park, this limestone cave system is one of the largest by volume and features an underground river. Guided tours are available, and the park is known for its
safety and ecological care.
Postojna Cave, Slovenia - A tourist favorite, this cave system includes a train ride through stunning formations. It’s well-lit, easy to navigate, and is famous for its underground train and dramatic formations,
it’s been welcoming tourists for over 200 years..
Waitomo Glowworm Caves, New Zealand - Famous for its glowing inhabitants, this cave offers boat tours with a magical experience under a ceiling of bioluminescent glowworms. It’s magical and very safe for families and first-time spelunkers.
Fingal’s Cave, Scotland - Located on the uninhabited island of Staffa, this sea cave is known for its acoustics and hexagonal basalt columns. It’s accessible by boat during calm weather.
Lechuguilla Cave, USA - Known for its unique geological formations and scientific significance.
Shuanghedong Cave Network, China - One of the longest cave systems in the world.
Ox Bel Ha System, Mexico - A large underwater cave system accessible through cenotes.
Mulu Caves, Borneo - Contains the largest cave chamber by surface area, the Sarawak Chamber.
Blue Grotto, Italy, is known for its surreal blue light, it’s a must-see on Capri Island.
The Tunnel of Love in Ukraine is a breathtakingly romantic spot!. Located near Klevan, Rivne Oblast, this railway tunnel is surrounded by lush green arches, creating a magical, fairy-tale-like atmosphere.
Originally built for industrial purposes, the railway is still in use, with trains passing through a few times a day. Over time, the trees naturally shaped themselves around the tracks, forming the
stunning tunnel that has become a favorite destination for couples and photographers alike. The tunnel is about 4 kilometers long and looks mesmerizing in every season—whether it's covered in vibrant
green foliage in summer or dusted with snow in winter. Many visitors believe that making a wish here can bring good luck in love!
The Guoliang Tunnel in China is an engineering marvel and one of the most breathtaking tunnels in the world! Carved into the side of the Taihang Mountains in Henan Province, this tunnel was built by
villagers who wanted to create a safer passage to the outside world. The tunnel is famous for its dangerous yet mesmerizing design, with sharp turns and unpredictable dips that make driving through
it a thrilling experience. It has since become a major tourist attraction, drawing adventurers and photographers from around the world.
Opened: May 1, 1977.
Length: About 1.25 kilometers (0.78 miles).
Width: 4 meters (13 feet)—just enough for one-way traffic.
Height: 5 meters (16 feet).
Construction: Dug by hand using basic tools, taking five years to complete.
Unique Features: Over 30 "windows" carved into the tunnel walls, offering stunning views of the surrounding cliffs.
Tunnel of Love, Guoliang tunnel, Laerdal tunnel, Tokyo Bay Aqua-Line, Glow Worm tunnel, and Paris Catacombs are the most truly beautiful and stunning tunnels in the world, both natural and man-made!
Tunnel of Love, Ukraine – A lush, green railway tunnel that looks straight out of a fairy tale.
Guoliang Tunnel, China – Carved into the side of a mountain, offering breathtaking views.
Laerdal Tunnel, Norway – The longest road tunnel in the world, featuring mesmerizing lighting effects.
Tokyo Bay Aqua-Line, Japan – A tunnel that transitions into a bridge, offering a unique driving experience.
Glow Worm Tunnel, Australia – A former railway tunnel now home to thousands of glowing worms.
Paris Catacombs, France – A hauntingly beautiful underground tunnel lined with historical bones.
The Glow Worm Tunnel in Australia is a magical place! Located in Wollemi National Park, New South Wales, this 387-meter-long tunnel was originally built in the early 1900s as part of a railway for the mining industry.
Over time, it was abandoned, and nature took over—creating the perfect habitat for thousands of bioluminescent glow worms. The tunnel is completely dark, making the glow worms appear like a starry sky.
The surrounding area features lush forests, towering rock formations, and scenic walking trails.
The Paris Catacombs are one of the most eerie yet fascinating underground sites in the world! Located beneath the streets of Paris, France, this vast network of tunnels serves as an ossuary,
holding the remains of over six million people. The catacombs were created as a solution to Paris’s overflowing cemeteries, with remains transferred here in nightly processions starting in 1788.
Over time, they became a tourist attraction, drawing visitors intrigued by their macabre beauty and historical significance.
Originally limestone quarries, later repurposed to store human remains.
Established in the late 18th century due to overcrowded cemeteries.
Known as "The World's Largest Grave".
The Delaware Aqueduct is the longest tunnel in the world, stretching 137 km (85 mi). It is a crucial part of New York City's water supply system, carrying about half of
the city's daily water needs from reservoirs in the Catskill Mountains. Built between 1939 and 1945, the aqueduct runs deep underground, reaching depths of 750 meters
(2,500 feet) in some places. Over time, leaks were discovered in the 1990s, leading to a massive $1 billion repair project that included constructing a bypass tunnel
beneath the Hudson River.
The Päijänne Water tunnel is an underground water tunnel in Southern Finland, stretching 120 km (75 mi), making it the second-longest tunnel in the world. It runs 30–100 meters
(100–330 feet) deep in the bedrock and supplies fresh water to over one million people in the Greater Helsinki area. The tunnel starts at Lake Päijänne, Finland's second-largest
lake, and ends at the Silvola reservoir in Vantaa. Water flows naturally downhill due to the tunnel’s slight slope, ensuring high-quality water with minimal processing.
The tunnel was constructed between 1972 and 1982 at a cost of approximately €200 million (adjusted for inflation).
The Gotthard Base tunnel is the longest railway tunnel in the world, stretching 57 km (35.5 mi) through the Swiss Alps. It connects Erstfeld in Uri to Bodio in Ticino,
providing a high-speed rail link between northern and southern Europe. It opened in June 2016, and is the deepest railway tunnel in the world, with a depth of up to 2,450 m (8,040 ft).
The Gotthard Base tunnel was designed to improve freight and passenger transport, reducing reliance on road traffic.
The Seikan tunnel is an incredible engineering feat in Japan, stretching 53.85 km (33.46 mi) and running 23.3 km (14.5 mi) beneath the Tsugaru Strait. It connects Honshu and Hokkaido,
serving both passenger and freight trains. Despite its impressive scale, passenger air travel between Honshu and Hokkaido remains more popular than rail, though the tunnel is vital for freight transport.
Opened: March 13, 1988
Depth: 240 meters (790 feet) below sea level
Rail Lines: Supports Shinkansen bullet trains and freight trains
Construction Time: 34 years (started in 1964, completed in 1988)
Purpose: Built after the 1954 Toya Maru ferry disaster, which led to over 1,400 deaths
The Channel tunnel, often called the Chunnel, is a 50.46 km (31.35 mi) undersea railway tunnel connecting Folkestone, England, with Coquelles, France, beneath the English Channel.
It is the third-longest railway tunnel in the world and has the longest underwater section of any tunnel at 37.9 km (23.5 mi). The tunnel was built to provide a fixed link between
Great Britain and mainland Europe, significantly reducing travel time compared to ferries. It consists of two rail tunnels and a service tunnel for maintenance and emergencies.
Opened: May 6, 1994
Depth: 75 meters (246 feet) below the seabed
Speed: Trains travel at 160–200 km/h (99–124 mph)
Operators: Eurostar (passenger trains) and Getlink (freight and vehicle shuttle trains)
The Lærdal Tunnel in Norway is the longest road tunnel in the world, stretching 24.5 km (15.2 mi). It connects Lærdal and Aurland, providing a ferry-free route between Oslo and Bergen.
The tunnel was designed with psychological considerations, using lighting and spacious sections to prevent driver fatigue and claustrophobia. It has no toll, making it a popular route for travelers.
Safety Features: Includes three large mountain caves with blue and yellow lighting to reduce driver fatigue.
Delaware Aqueduct, Päijänne Water tunnel, Gotthard Base tunnel, Seikan tunnel, Channel tunnel, Channel tunnel, and Lærdal tunnel are the most longest tunnels in the world.
These tunnels are incredible feats of engineering, cutting through mountains, under oceans, and across vast distances.
Delaware Aqueduct (USA) – 137 km (85 mi) – The longest water supply tunnel.
Päijänne Water Tunnel (Finland) – 120 km (74.6 mi) – Another massive water supply tunnel.
Gotthard Base Tunnel (Switzerland) – 57 km (35.5 mi) – The longest railway tunnel.
Seikan Tunnel (Japan) – 54 km (33.5 mi) – A railway tunnel with an undersea section.
Channel Tunnel (UK-France) – 50.5 km (31.4 mi) – The famous undersea railway tunnel connecting England and France.
Lærdal Tunnel (Norway) – 24.5 km (15.2 mi) – The longest road tunnel.
Asia is home to some of the most breathtaking bridges, blending architectural brilliance with cultural significance. Helix Bridge, Dragon Bridge, Langkawi Sky Bridge, Tokyo Bay Aqua Line,
Duge Bridge, Chengyang Wind and Rain Bridge, Khaju Bridge, Bandra-Worli Sea Link, Nine Arches Bridge, and Lucky Knot Bridge are the most stunning and famous bridges in Asia.
Each of these bridges has a unique story and design, making them must-visit landmarks.
Helix Bridge (Singapore) – A futuristic pedestrian bridge inspired by the DNA double-helix, illuminated beautifully at night.
Dragon Bridge (Vietnam) – A spectacular bridge in Da Nang that breathes fire and water during weekend performances.
Langkawi Sky Bridge (Malaysia) – A curved suspension bridge offering panoramic views of lush mountains and the Andaman Sea.
Tokyo Bay Aqua Line (Japan) – A unique combination of a bridge and an underwater tunnel connecting Kawasaki and Kisarazu.
Duge Bridge (China) – The highest bridge in the world, soaring 565 meters above the Beipan River.
Chengyang Wind and Rain Bridge (China) – A stunning wooden bridge built without nails, showcasing traditional Dong architecture.
Khaju Bridge (Iran) – A historic Persian bridge that doubles as a dam, adorned with intricate tilework.
Bandra-Worli Sea Link (India) – A modern cable-stayed bridge connecting Mumbai’s suburbs, offering breathtaking coastal views.
Nine Arches Bridge (Sri Lanka) – A colonial-era railway bridge surrounded by lush tea plantations.
Lucky Knot Bridge (China) – A mesmerizing red steel bridge with multiple intertwined pathways, resembling an infinite loop.
Bridges can be more than just functional—they can be breathtaking works of art!. Ponte Vecchio, Bastei Bridge, Pont du Gard, Helix Bridge, Puente Nuevo, Capilano Suspension Bridge,
Tower Bridge, Stari Most, Bixby Creek Bridge, and Charles Bridgeare are the most stunning bridges around the world; each of these bridges has its own unique charm, whether
it's historical significance, architectural beauty, or breathtaking surroundings.
Ponte Vecchio (Florence, Italy) – A medieval stone bridge lined with charming shops, dating back to 1345.
Bastei Bridge (Germany) – A surreal sandstone bridge perched over 600 feet above the Elbe River, blending seamlessly with the surrounding rock formations.
Pont du Gard (France) – A Roman aqueduct bridge over 2,000 years old, showcasing ancient engineering brilliance.
Helix Bridge (Singapore) – A futuristic pedestrian bridge designed to resemble the structure of DNA, illuminated beautifully at night.
Puente Nuevo (Spain) – A dramatic stone bridge spanning the deep El Tajo Gorge in Ronda, offering breathtaking views.
Capilano Suspension Bridge (Canada) – A thrilling suspension bridge hanging 230 feet above the Capilano River, surrounded by lush forest.
Tower Bridge (London, UK) – One of London’s most iconic landmarks, combining historical charm with modern functionality.
Stari Most (Bosnia and Herzegovina) – A reconstructed Ottoman bridge with a mesmerizing hump-backed shape over emerald waters.
Bixby Creek Bridge (California, USA) – A picturesque coastal bridge in Big Sur, famous for its stunning ocean views.
Charles Bridge (Prague, Czech Republic) – A historic bridge adorned with 30 baroque-style statues, offering a magical stroll over the Vltava River.
The Ponte Vecchio, meaning "Old Bridge" in Italian, is one of Florence's most iconic landmarks. It spans the Arno River at its narrowest point and has a fascinating history dating back to Roman times.
Originally, the bridge was constructed with stone piers and a wooden superstructure, but it was destroyed by floods multiple times before being rebuilt in 1345. The architect Taddeo Gaddi is credited
with designing the current structure, which was revolutionary for its segmental arch design, allowing for better flood resistance and navigation. Throughout its history, the Ponte Vecchio has been home
to shops and merchants, a tradition dating back centuries. Initially, butchers and tanners occupied the bridge, but in 1595, Ferdinand I ordered that only goldsmiths and jewelers could set up shop there,
a tradition that continues today. During World War II, the Ponte Vecchio was the only bridge in Florence spared from destruction by the retreating German army, allegedly due to a direct order from Hitler himself.
Today, the bridge remains a major tourist attraction, bustling with visitors admiring its historic charm, glittering jewelry shops, and breathtaking views of the Arno River.
The Bastei Bridge, located 40 km from Dresden, Germany, is a breathtaking sandstone bridge in Saxon Switzerland National Park; it sits atop towering rock formations, offering stunning
panoramic views of the Elbe River and surrounding landscapes.
The Bastei rock formations were shaped by water erosion over millions of years..
The first wooden bridge was built in 1824 to connect the rocks for visitors..
In 1851, the wooden bridge was replaced with the current sandstone bridge, making it more durable..
The bridge leads to the ruins of Neurathen Castle, a medieval fortress that once controlled the Elbe Canyon.
The Pont du Gard is an ancient Roman aqueduct bridge located in southern France, near the town of Vers-Pont-du-Gard; it was built in the first century AD to carry water to the Roman colony of Nîmes.
The bridge stands 48.8 meters (160 feet) high and features three tiers of arches.
Constructed without mortar, using precisely cut Shelly limestone.
It once transported 40,000 cubic meters of water per day over a distance of 50 km (31 miles).
The aqueduct was in use until the 6th century, but lack of maintenance led to its decline.
After the fall of the Roman Empire, it was repurposed as a toll bridge.
It was designated a UNESCO World Heritage Site in 1985 due to its exceptional preservation and historical importance.
The Helix Bridge, located near Marina Bay Sands, Gardens by the Bay, and the Singapore Flyer, is a stunning pedestrian bridge in Singapore, linking Marina Centre with Marina South in the Marina Bay area.
Inspired by the double-helix structure of DNA, symbolizing life and continuity.
Designed by Cox Architecture, Arup, and Architects 61, blending engineering and artistry.
Made of stainless steel, stretching 280 meters (920 feet) across Marina Bay.
Features four viewing platforms offering breathtaking views of the Singapore skyline.
At night, the bridge is illuminated with red and green lights, representing the DNA bases cytosine, guanine, adenine, and thymine.
Construction began in 2007 and was completed in 2010.
Won the World’s Best Transport Building award at the World Architecture Festival in 2010.
Recognized for engineering excellence by the Building and Construction Authority (BCA) in 2011.
The Puente Nuevo ("New Bridge") is the most famous bridge in Ronda, Spain, spanning the dramatic El Tajo Gorge.
The previous bridge, built in 1735, collapsed in 1741, killing 50 people.
Reconstruction began in 1759 and took 34 years to complete.
Designed by José Martin de Aldehuela, it stands 105 meters (344 feet) high.
Built entirely of stone, with three massive arches supporting the structure.
The bridge connects La Ciudad (Old Town) with El Mercadillo (New Town), making it a vital link for the city.
A chamber above the central arch was used as a prison and allegedly as a torture chamber during the Spanish Civil War.
The Capilano Suspension Bridge, located in North Vancouver, British Columbia, Canada, is one of Vancouver's most famous attractions, offering a thrilling walk 230 feet (70 meters) above the Capilano River.
Originally built in 1889, the bridge was made of hemp ropes and cedar planks.
It was later rebuilt with wire cables in 1903 and has undergone several renovations since.
The bridge spans 140 meters (460 feet) and is surrounded by lush rainforest.
The park also features Treetops Adventure, a series of suspended footbridges, and Cliffwalk, a narrow pathway along a granite cliff.
Tower Bridge is one of London's most iconic landmarks, spanning the River Thames near the Tower of London.
Built between 1886 and 1894, designed by Horace Jones and engineered by John Wolfe Barry.
A bascule (drawbridge) and suspension bridge, allowing ships to pass through.
The twin towers stand 213 feet (65 meters) high, connected by walkways.
Originally powered by steam-driven hydraulic pumps, later converted to electro-hydraulic in 1972.
The bridge lifts about 800 times a year, down from 6,000 times in 1894.
Often mistaken for London Bridge, leading to an urban legend about an American buying the wrong bridge.
The high-level walkways were closed in 1909 due to crime but reopened in 1982.
Offers panoramic views of London from glass floors 42 meters above the Thames.
The Stari Most ("Old Bridge"), declared a UNESCO World Heritage Site in 2005, recognizing its cultural significance, is a stunning 16th-century Ottoman bridge in Mostar, Bosnia and Herzegovina;
it spans the Neretva River, connecting the two sides of the city.
Commissioned by Suleiman the Magnificent in 1557.
Designed by Mimar Hayruddin, a student of the famous Ottoman architect Mimar Sinan.
The bridge is 30 meters (98 feet) long and 24 meters (78 feet) high, with a single stone arch.
Protected by two fortified towers: Halebija Tower and Tara Tower, known as the "bridge keepers".
Destroyed on November 9, 1993, during the Bosnian War, after being shelled by Croatian forces.
Rebuilt between 2001 and 2004, using original techniques and materials, overseen by UNESCO.
The Bixby Creek Bridge, also known as Bixby Bridge, located 15 miles south of Carmel, California, along Highway 1, is one of the most photographed and iconic bridges in California, located along the Big Sur coast.
Built in 1932, it was designed to improve access to Big Sur, which was previously cut off during winter.
A reinforced concrete open-spandrel arch bridge, stretching 714 feet (218 meters) in length.
Stands 260 feet (79 meters) above Bixby Creek, offering breathtaking views of the Pacific Ocean.
Originally constructed for $199,861, which would be around $3.64 million today.
Recognized as one of the most beautiful bridges in the world due to its graceful design and stunning coastal setting.
The Charles Bridge is one of Prague’s most famous landmarks, spanning the Vltava River and connecting the Old Town with the Lesser Town.
Commissioned by King Charles IV, construction began in 1357 and was completed in 1402.
Designed by Peter Parler, the architect behind St. Vitus Cathedral.
Built using Bohemian sandstone, featuring 16 arches and three bridge towers.
Originally called Stone Bridge or Prague Bridge, it was renamed Charles Bridge in 1870.
The bridge was the only crossing over the Vltava River in Prague until 1841, making it a vital trade route.
Legend says construction began at 5:31 AM on July 9, 1357, following a numerological sequence 135797531 for good luck.
The bridge is adorned with 30 baroque statues, mostly replicas, as the originals were moved to the National Museum.
Today, the bridge is pedestrian-only, bustling with street musicians, artists, and vendors.
Offers stunning views of Prague Castle and the city’s skyline.
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