A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

This 1920s Dutch barge is now a floating bookstore.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

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

The most confusing clock in New York.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Though its celestial ceiling is impressive, the true star is the vast collection of French books.

A celebration of capitalism in Midtown.

Try not to get slimed in Tribeca.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

Cryptic messages embedded in the New York City sidewalk.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A surrealist timepiece by the artist of melting clocks.

This Parisian fountain is a little bit fantasy and a little bit nightclub.

This Parisian café sticks almost exclusively to an ethos of reuse.

This knockout museum lies in a sleepy corner of London.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

This London plaque marks the spot where David Bowie's famous alien made his debut.