The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

Where the lovelorn find a home for their sentimental keepsakes.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

Climb inside an iron crystal magnified 165 billion times its normal size.

This statue once earned the distinction as one of the "Three Major Disappointments of the World."

Singapore's landscaping project is home to 18 incredible Supertrees.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

France's most famous cemetery, with some of its most curious tombs.

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

A small and surprising passageway in Saint Petersburg devoted to the Beatles.

Monastery, army base, and infamous Soviet Gulag in the far Russian north.

This nostalgic Russian museum is full of USSR cultural artifacts from the 1970s and 80s.

World's largest bell sits on the grounds of the Kremlin in Moscow.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

An 18th century wonder of the world, lost in WWII, re-created at the Catherine Palace.

This Russian religious complex is a Frankenstein's chapel that includes influence from almost all the major faiths.

Immortal combat in a Moscow museum.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

The smallest museum in Basel, Switzerland, is a two-foot-by-two-foot window in the door of a 600-year-old house.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

The Swiss artist's bulbous and overgrown shape-shifting sculpture controversially graces the center of Bern.