17th century streets hidden under Edinburgh were once a breeding ground for the black death.

A million and a half tons of earth were used to create one of the world's largest land sculptures.

At high tide this strange footbridge appears to have no purpose whatsoever.

St. Mary's Asylum was isolated and abandoned before being converted into a Bed and Breakfast.

The largest cave chamber in Britain—big enough to fit a whole cathedral inside.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.