A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

Largest lake in Great Britain measured by surface area.

Fascinating town where normal life interfaces with the occult.

Vermont's hills are alive with the sound of music at this historic hotel.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

A mysterious castle built as a monument to lost love.

Watch butterflies take flight before you fly.

The mysterious megaliths have enchanted and intrigued visitors for thousands of years.

Hear the quietest sound from across the dome.

Red sandstone structures dominate this landscape, which has been inhabited for some 5,000 years.

A charming desert roadside bakery that produces 10 times more bread daily than it has residents in its town.

The echoes of a railroad town that solemnly mark the end of the line.

For decades, the largest tungsten producer in the U.S. was located in a spectacular setting in the high Sierra Nevada, with some of the workings over 11,000 feet.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

A monument to the frontier doctor who came up with the idea of delineating highways with a painted line.

This spectacular track has run continuously since 1882.

The fifth-longest natural arch in the world, and the longest outside China.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

A winding, cliffside stretch of road overlooking the Delaware River.

Famously misunderstood wonder of the ancient world

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

This is the oldest Roman-made bridge in the city still existing in its original state.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.