A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

Denmark’s never-ending bridge.

Packed with geological formations, an ancient river, and taxidermied seals, this overlooked coastal cave system is worth a spelunk.

Once one of the largest sites of silver deposits in Italy.

Mysterious tombstones thought to be remnants of Atlantis.

At an estimated 3,800 years old, this olive tree is one of the oldest on earth.

The decommissioned steam engine’s whistle can still be heard three times a day at one of Japan’s oldest train stations.

This park boasts a unusual collection of curious monuments from around the world, from Micronesia to Antarctica.

The sunlight passing through the opening of this huge cave system creates a magical effect.

A museum specifically dedicated to the Trabant, one of the iconic automobiles of the GDR.

A dilapidated space station with overtones of 'Alien' and 'Bladerunner' featuring a multiplayer games galore.

A decomissioned facility where the German "Transrapid" maglev trains were once tested.

A collection of antique telescopes dot the halls of the university's astrophysics department.

A charming and enigmatic sculpture of a lynx haunts the park of Kellinghusen.

This unique abacus hanging in the Technical University of Munich actually tells the time.

Art historians have debated the identity of this medieval stone rider since the 19th century.

This private museum is packed with 20th-century traffic and technology artifacts.

A tiny, intricate model railway system.

A 1:2 billion-scale solar system leads visitors into this German university town.

Home to the world’s oldest seismograph and a four-ton steel ball that makes its own earthquakes.

The zoological collection at the Hessisches Landesmuseum hosts some of the world's oldest habitat dioramas.

Oberweissbacher Bergbahn - a broad-gauged cable car capable transfering railcars.

This German museum devoted to the simple wonders of salt is actually built over an old saltworks.

It has an American Dream Car exhibit, Europe's largest Formula One collection, and many, many mannequins.