The second-longest continuous wall on the planet protects a hidden secret in the deserts of India.

A lake with hundreds of ancient skeletons surrounding it. The surprise is what killed them.

A stunning blue-green lake located in the Terskey Alatau mountain range.

Extremely isolated Silk Road caravanserai in the middle of nowhere.

A network of concealed passageways lies within a busy London Underground station.

Salt cured mummies continue to turn up in this Iranian mine.

One of the world's largest salt caves is filled with fragile salt sculptures, salt rivers, and huge salt megadomes.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

This small shrine is dedicated to the designer of the first Russian fighter jet and his brother, who became Chairman of the Presidium of the Supreme Soviet.

A giant concrete Brutalist water tower in suburban Johannesburg.

The remains of diamond fever taken over by the desert.

A powerful tribute to the victims who suffered under Ethiopia's most devastating regime.

This star-shaped military outpost is now simply trying to protect itself from neglect.

With a facade that measures just 107 centimeters, this five-story building is one of the skinniest in Europe.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

Huge standing stones mark a site of megalithic mystery.

Banksy gives themself artistic license with this piece of London street art.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

A monument dedicated to the civil uprisings that took place during the Pots and Pans Revolution.

The place to be if you love vintage Swedish cars.

This trio of stone spires claims to be the only preserved medieval execution site in Europe.

Enigmatic bug-like sculptures mystify drivers along a Swedish highway.

Sweden's "good old days" painstakingly re-created in a model village.