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

Architectureal fantasy quarter of Rome.

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

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

Ancient ruins hidden underneath a modern luxury hotel.

A sculpture serving as an homage to Pope John Paul II.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

A network of underground water channels that dates back to the Middle Ages.

This skeletal, unfinished Gothic church once housed a miraculous masterpiece by Raphael.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

The largest prehistoric cemetery on the Balearic Islands dates back over 2,500 years.

This "flat geyser" bubbles up out of the ground periodically like a disappearing river.

This spectacular bridge is part of an abandoned train line that once connected Mallorcan capital to the southeastern coast.

This abandoned gold mine found a second life as a post-apocalyptic film set.

This small Spanish village still pays homage to the Spaghetti Western films that were shot there in the 1960s.

Red, white, and blue painted steps along with a Union Jack celebrate the outcome of Gibraltar's 1967 referendum.

Single runway interrupted by a busy road that cuts across its middle.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

In one of the smallest countries in the world stands an original Salvador Dalí sculpture.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

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