This North African stone complex is considered to be the oldest astronomical observatory on Earth.

A harrowing trail up a mile-high mountain.

A sacred mountaintop temple offers a fine cup of tea to visitors who can survive the journey.

Catch a ride through the Pennsylvania countryside on this historic narrow-gauge railroad.

This library dates back to the late 17th century and was one of the first public lending libraries in England.

An abandoned tower once used to study the cosmos hides within a thicket of greenery.

This magnificent arch is all that remains of a former smelt mill.

An iconic waterwheel in the Pennine Hills marks the location of one of Britain’s most profitable lead mines.

These remarkable cascades are the jewels of Upper Tees.

For six months of the year, three giant mirrors direct a pool of sunshine onto this otherwise occluded town.

This abandoned amusement park was built on a site with a dark history.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

Art Deco stylings conceal the true nature of this bridge.

You can cross from one country to another in a single hop on this little bridge.

Take a ride back in time with a steam locomotive trip through Eritrea’s mountainous countryside.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

A railroad lift bridge that was only lifted once and became obsolete before construction was finished.

A painfully obvious spy house sits right across the street from the Russian Embassy.

One of the last schoolhouses constructed in the early 20th-century still standing in Montgomery County.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

A reproduction of a giant humanoid "fossil," a hoax buried locally for construction crews to find and gain national attention.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.