Places Jochen Duckeck Wants to Go

A Roman water tunnel still flows 2,000 years on.

The longest pedestrian tunnel in the world.

One of the world’s few undersea pedestrian tunnels connects Honshu and Kyushu islands.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

After sitting abandoned for decades, this historic mine is now the only publicly accessible chalk room and pillar mine in North America.

A stunning silver lining to global warming's gloomy cloud.

The wartime boat shelter now doubles as an underground concert hall where musicians play on rafts along the waterway.

A prehistoric limestone cave entered through a spectacular natural rock arch.

This narrow cave is revered in Japan as the womb of Mount Fuji.

Three generations of intrepid collectors display their curious artifacts in a homemade museum right next to the caves they discovered.

A cave with a continual human presence from 20,000 BC outside of Vela Luka on the island of Korcula.

A lava tube cooled to form this long tunnel that stays chilly even at the height of summer.

This underground cave located in the most barren reaches of Idaho is filled with ice year-round.

This trail leads to a mine that was used as a sanctuary during the Great Fire of 1910.

It was once used as a classroom to teach mining skills to local high school students.

This 14th century wine cellar is home to the oldest barrel-stored wine in the world.

This ancient Roman cistern has been the source of many legends throughout the centuries.

An underground venue, buried for 200 years, now open as a unique whisky tasting venue.

The final resting place for the remains of 143 Habsburg royalty.

This massive underground salt mine now holds a sci-fi theme park in its depths.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

While walking down Mazatlan's historic boardwalk, visitors are surprised to find their ocean view interrupted by a gateway to hell.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.