The oldest house of worship in Palm Beach has a wonderful tropical garden.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

A grand New York post office that is home to mailman Santas, scraps of postal history, and a pneumatic mail system.

Where now stands a 42-story condominium tower of marble, glass and steel was once the central market of New York’s slave trade.

This unassuming bridge is most likely one of Michelangelo's unfinished masterworks.

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

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

Architectural monsters are devouring this palace's every door and window.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This basilica is dedicated to two saints, one of which is known more for his famous quote.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

This historical swimming pool near Miami is emptied and refilled each day with naturally filtered water.

This historic site situated in the Northwood shores neighborhood houses the remains of a forgotten town.

This spooky road cut through a mound of ancient coral might be haunted by a witch.

Grab a slice of pizza next to the remains of the "human monkey" who ran for mayor.

This railroad and oil tycoon's lavish estate now stands as a time capsule of the Gilded Age.

This 25-foot tall clock tower commemorates the start of one of America's foremost shopping districts and the end of the historic Palm Beach Pier.

A memorial dedicated to a highly decorated Marine and Korean War veteran, who also happened to be a horse.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

The singer, actor, and activist lived here during his final years, and now it’s a museum dedicated to his legacy.

The oldest Methodist church in the United States has been spreading the good news for over two centuries.

The last remnants of what was once one of the world's grandest hotels can now be found in a Manhattan subway station.