This one-woman cemetery was a small civil rights victory.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

This amazing 15th-century mural remained hidden in plain sight for centuries.

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

A mysterious demonic figure peers down from its perch within the gorgeous Chester Cathedral.

A bright little alley in La Boca is a part of tango history.

Its buzzing collection honors vibrator history.

Home to the world's oldest functioning orrery.

One of the world's smallest prisons boasts just two small cells.

A gateway to a mysterious network of underground tunnels.

Buenos Aires' city of the dead contains some very famous remains, including Eva Perón.

A tiny, heartwarming piece of art hiding in plain sight.

This dreamy street will transport you to wintertime in Victorian England.

Believed to have once stored either human remains or rice wine, thousands of mysterious stone jars lie in ruin.

A tangible and sobering reminder of an atrocity that took place during a secret war.

You can row a boat through this ancient underground reservoir.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

This small museum in a former church crypt contains artifacts of the Elephant Man, Jack the Ripper and Florence Nightingale.

The largest greenhouse in the world is home to over one million types of plants.

The remains of Crystal Palace Great Exhibition of 1851.

Northern Ireland's Brobdingnagian stepping stones.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This South London cemetery holds the remains of more than 15,000 people.