Rome's semi-secret peephole vista is also a former Crusader stronghold.

A dead saint, a deadly poison, and a mysterious holy ooze.

This twisty sign depicts the chain's first logo.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

The oldest liquor store in the country is a model of resilience and mischief.

This groundbreaking 16th-century map is known as "America's birth certificate."

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

Despite being considered a thoroughly American sport, basketball's oldest surviving playing field is found in the basement of a Paris YMCA.

Indents in the pavement are all that remain from a grisly death machine in Paris.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

It should come as no surprise that the best view of the Hollywood sign is from Batman's lair.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

An enormous, inside-out glass globe built in 1935.

A Montreal deli that was so beloved that it was allowed to circumvent their laws of language.

A historic neighborhood church is reborn as a psychedelic arts collective.

Largest Roman Catholic church in North America.

The narrowest street in Paris.

Historical figures from New York City's Catholic community reside in Midtown.

The house where John Wilkes Booth conspired with his co-conspirators.

A historic arena where the Beatles played their first concert in the U.S.

A clone of a cloned tree that was so important it allegedly had its own guards.