The last Viking king of Denmark is buried inside the crypt of this cathedral.

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

A crumbling hospital from the 1850s on Roosevelt Island.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

The first passenger cable car in the world.

Europe’s oldest natural human mummy.

Ever hear of the Milazzo Cage?

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

Rome's first modern graffito is all that is left of a peaceful protest from the 1970s.

This curious, round temple is the oldest still-standing marble building in Rome.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

A rather vulgar example of the transition from Latin to the Italian vernacular.

A fortified medieval basilica on the Caelian Hill preserves extraordinary frescoes and one of Rome's most beautiful hidden cloisters.

This ancient market is often referred to as the oldest shopping mall in the world.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

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

The mystic whose incorrupt corpse still attracts the faithful.

A huge enchanting public park just outside the ancient walls of Rome.

One of the most important yet well-hidden museums dedicated to the history of medicine.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

One of seven Jewish catacombs in Rome and one of only two open to the public.

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

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