Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

In its day this historic fort held 100 cannons pointed in almost every direction to protect New York.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

The ruins of an ancient Mayan city, beautifully preserved and only accessible by boat.

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

Famously misunderstood wonder of the ancient world

The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

This stone complex marks the urban center of a lost civilization.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

A crumbling hospital from the 1850s on Roosevelt Island.