The nuns here cultivate silk to weave some of the finest scarves in the world.

One of the earliest large-scale "hyper" roofs in the U.K. is now a derelict roadside attraction.

A coastal monument honors one of Mexico's most notable immigrant groups.

The severed head of a 17th-century Irish martyr lies within an intricate golden shrine.

The last of Amsterdam's original sea level markers remaining in place.

The odd depiction of the Virgin Mary and baby Jesus is rooted in the Catholic Church's eradication of Catharism.

This gigantic monument hidden in the woods was built to thank the Dutch for sheltering Belgian refugees during World War I.

An artsy hidden staircase leads to breathtaking views of San Francisco.

J.R.R Tolkien, C.S. Lewis, and other "Inklings" met at the Oxford pub to discuss the now legendary fantasy stories they were writing.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

This hauntingly beautiful cemetery outside a medieval citadel is full of winding paths and ivy-covered graves.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

A Byzantine church containing the holy remnants of three saints sits atop the site of an ancient temple.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

A mysterious ancient elephant said to possess magic powers is now the symbol of a Sicilian city.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.