A church now sits over the site of one of the worst urban disasters of early 19th-century America.

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.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

2300-year-old Roman road connecting the empire.

The former home of an Italian artist is now a shrine to his ambitious works.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

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.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

A Nesting Doll of Churches.

Ancient ruins hidden underneath a modern luxury hotel.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

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

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."

A statue representing a lost Roman profession that was vandalized for centuries.

A massive marble foot is tucked away in a small alley near the Pantheon.

Plaques on its facade commemorate the Tiber's most destructive deluges.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Malcolm X's house during his most formative years faces an uncertain future.

The eccentric mansion of one the most popular horror authors of modern times.

One of the oldest Catholic churches in the U.S., situated just east of Gettysburg.