Antique cinematography artifacts fill this museum dedicated to the inventors of the moving picture.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

This influential Renaissance-era library was once the haunt of kings and monks.

The little church's beautifully frescoed ceiling has earned it the nickname “the Sistine Chapel of Madrid.”

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

This 18th-century project to build the world's tallest gravity dam was never completed.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

A lush indoor jungle fills this bustling Madrid transportation hub.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

This charming, medieval walled village is Spain's first "book town."

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

The eclectic observatory castle of a 19th-century astronomer and explorer.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

Depending on who you ask, this controversial treehouse is either a charmingly creative child's playhouse or an illegal encroachment on public land.

A restaurant with an extensive Irish whiskey bar also has several first editions of famous works by Irish authors.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

Wander among the abandoned ruins of this once-powerful medieval town.

The ruins of a medieval monastery named after a type of tree.

A moody and picturesque riverside ruin overgrown with vegetation.

A rocky Irish outcropping with a history of wealth, conflict, and ruin.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

This 5,300-year-old tomb with mysterious carvings crowns an Irish mountain.

A botanically themed auditorium blooms within the world’s last operating double-decker theater.