The chaotic studio of one of the 20th century's most important artists has been preserved down to the dust.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

A beautiful Greco-Roman structure houses a well once believed to have healing powers.

The commemorative stone column conceals a secret laboratory.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

The narrowest street in Paris.

Imagine having a street run right through your home, or better yet, a historic bridge three stories high.

Stockholm's narrowest alley is barely over two feet wide.

This ordinary street was made infamous by a legendary visit from the devil.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

This charming old building's loose connection with the Scottish Reformer is what saved it from demolition after it split apart.

This small museum in a 17th-century building honors three iconic Scottish writers.

Experience what life was like in Ireland during the Viking and medieval ages.

This enormous World War II relic is one of the largest wooden structures in the world.

One of two lighted lanterns hung in the church belfry on the eve of the Revolutionary War to warn that the British were on their way.

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

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

The Sun King's military models, saved from the Louvre.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Abandoned railway line circling the city of Paris.

This bridge was constructed from the rubble of the infamous Bastille.