Ancient paintings known as the "Sistine Chapel of Cave Art."

Paris' linguistic guide to the international language of, yes, love.

The oldest stone house in Paris was built by its most famous alchemist.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The largest tidal whirlpool in the Western Hemisphere.

A strange mark in the stone fence of a cemetery fabled to have been made by the Devil himself.

This 19th century granite fortification is one of the most well preserved forts in New England.

Turns out you can see the world without ever leaving Maine.

Secret Swing.

A unique collection of Science Fiction, Fantasy, and everything in-between.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

A tunnel with windows, so you don't miss out on the impressive views.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

What once sat in the world’s spotlight is today a largely disused ghost complex.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

A series of caves, tunnels, and wells filled with fascinating figures and symbols.

The hallucinogenic center of the ancient world.

A taste of Middle Earth, in the middle of the Bayou City.

Hidden in the New Mexico desert southeast of Roswell, nine small deep lakes formed inside sinkholes.

A rocky shelter in the desert hides one of the largest concentrations of cave paintings in Mexico.

A planned settlement in Pennsylvania once housed the aristocratic refugees of the French Revolution.

A magical, macabre wax museum, beloved by locals, uses real artifacts to depict an assassination from the French Revolution.