The remains of what was, not so long ago, the world's largest city.

For six months of the year, three giant mirrors direct a pool of sunshine onto this otherwise occluded town.

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.

For 20 years, this whale skeleton has been slowly dripping oil on the floor of the museum where it hangs.

In the woods of New Jersey lie the ruins of a munitions village abandoned after World War I and the remnants of a 1920s wooden racetrack.

The world's first purpose-built motor racetrack was destroyed by the outbreak of two world wars.

An elevator into the Baltic Sea.

The forest that inspired Winnie-the-Pooh's Hundred Acre Wood can be found outside London.

One of the few surviving street funiculars in the world.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

These medieval monastery ruins are surprisingly overlooked by most tourists.

One of the world's steepest streets seems to have houses sliding down it.

At high tide this strange footbridge appears to have no purpose whatsoever.

An abandoned theme park with a strange and tumultuous past.

The world’s first hotel to be run by robots.

One of the world's tallest statues is also one of its most hated.

Its impressive still-working beam engine is a thing of beauty for engineering history fans.

One of the most poignant ruins of the Chernobyl nuclear disaster, the local football team's stadium has been quickly reclaimed by nature.

Tubing through a cave lit with glowworms is a magical underground experience.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

The famed architect designed this Minnesota gas station of the future with a lookout tower.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.