At more than 5,000 years old, these structures are among the oldest free-standing stone buildings in the world.

Italian cave with exceptional acoustics and an unsavory history.

The world's most active stratovolcano is almost always erupting.

Largest necropolis in the Mediterranean.

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

A Nesting Doll of Churches.

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

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Architectureal fantasy quarter of Rome.

Erotic art covers the walls of the largest ancient pleasure palace.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

Dynastic Home of the De Piro Family.

This 50-foot-deep sinkhole created in the 14th century is home to rare plants and fungi.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

This splendid mosaic embodies ancient Rome's fascination with the exotic allure of Egypt.

The city of Palestrina was built around this magnificent terraced sanctuary dedicated to the pagan goddess Fortuna.

Isaac Newton's former home, where the famous apple tree still stands.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The oldest of the three remaining bridges in England with buildings on top of them.

Largest lake in Great Britain measured by surface area.

Macabre astrological automaton clock dating to the late 1400s.