Monasteries on rock pillars, once accessible only by frayed ropes.

This ancient town is full of stunning Ottoman architecture and streets so narrow trash collection is done by donkey.

The ruined doorway is a portal to the building's turbulent and torturous past.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

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

Where commuters walk through remnants of an ancient Greek necropolis.

Large collection from the 3rd millennium BCE.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Greenery cloaks this serene sculpture inspired by the famous Lost Gardens of Heligan.

This 5,300-year-old tomb with mysterious carvings crowns an Irish mountain.

Although it appears ancient and mysterious, the quirky folly was actually built 200 years ago by an eccentric estate owner.

A hill carving of the legendary dragon that terrorized the village of Bures in the Middle Ages.

More stones than Stonehenge, all scattered within a windswept landscape sure to enchant 'Outlander' fans.

A dark Victorian well house now plays host to mystical waters and pagan shrines.

Artwork tucked within the trees greets visitors with surreal sonic experiences.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

A walkable map of the world, made from soil and stone by one man.

This massive chalk hill carving is one of England's most beloved giant horse geoglyphs.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

A scenic canyon with thick forests and historic ruins.