At 207 feet, one of the world's longest continuous escalators.

Home to items never before seen by the public.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Africa's Venice on stilts.

These homes carved into the mountains seem to defy the laws of nature.

The central mosque of this Mali town is entirely built from mud.

Where thousands of slaves passed through the "Door of No Return."

The world's largest church atop a political fault line.

The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

One of the last active volcanoes on the Eastern seaboard.