Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A marvel of Byzantine engineering under the streets of Istanbul.

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

Go inside to really appreciate this 500-year-old technological masterpiece.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Jesus' footprints and the first catacombs in the world.

2300-year-old Roman road connecting the empire.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

A Nesting Doll of Churches.

It houses the remains of a 17th-century version of the Titanic.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.

An abstract monument to a symphonic composer.

A subterranean house of worship carved right out of the bedrock.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

An 18th century wonder of the world, lost in WWII, re-created at the Catherine Palace.

The Guardian of Tallinn.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Cold war icon and onetime "hole" in the iron curtain.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Old Danish castle immortalized in Shakespeare's Hamlet.

There has been an astronomical clock on this spot since the 14th century.