Unrepaired walls from a 1920 anarchist bomb attack.

The "Seinfeld" diner.

An artist's cute bronze subway sculptures belie his violent artistic past.

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

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

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

New York City's smallest piece of private property.

A semi-scholarly approach to sex.

Elevated freight railway turned wildly successful urban park.

Tucked in the back of this amazing antique store is an important piece of medical history.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

The entire known universe of the ancient Etruscans is held inside this bronze model of a sheep’s liver.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Largest necropolis in the Mediterranean.

Rome's ancient Etruscan rival, now a park full of ruins.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

A Nesting Doll of Churches.