The oldest lighthouse on America's west coast no longer needs keepers, yet they maintain the site anyhow.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

A total of 14 men held the title of "president" before George Washington—their historical legacies are enshrined in the lobby of a hotel.

Journey inside the bowels of this sperm whale sculpture.

This abandoned psychiatric hospital once housed more than 4,000 patients in the middle of a quaint New England town.

This park is home to a massive bird sanctuary. And maybe buried treasure!

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The Devil’s own choice when he needs a drink in Brussels.

A preserved portion of an ancient Athens barrier is displayed in a hotel basement.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

A forgotten "city of water" underneath the famous Trevi district.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

This large, circular tomb is the final resting place of the first emperor of Rome.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

In one of the world's smallest countries, a royal's personal winery is open to the public.

Featuring a meatless buffet fit for kings, this family-owned Zurich eatery is considered the oldest vegetarian restaurant in the West.

These waste baskets play a few risque messages to discourage littering.

This 16th-century house tells the city's history through old artifacts and quirky tales.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

You may get stranded and everyone's peeing in the water, but at least there's cocktails!

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.