Thanks to an acoustic anomaly, this unassuming stone bench has heard one hundred years of secrets.

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

No one knows who painted this mysterious mural in a Penn State basement.

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

This house's itty bitty size means no humans allowed.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

This 47-story "M" needed 20 years to be completed

One of the world's oldest universities houses an incredible collection of anatomical models, mummified body parts, and human bones.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A 19th-century time capsule of travel, fiction, and historic texts still available to the public.

This Bordeaux parking garage has 712 indoor spaces, and one outdoor.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

Yo, Adrian!

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

This elaborate towering structure was once famed for its revolutionary height.

A 142-foot-tall Q-tip on Bristol's skyline.

This funky former tobacco factory is one of the most striking examples of Madrid's cultural diversity.

A quaint hamlet of nine cottages around a small green near Blaise castle.

Shrapnel, dynamite, bullets and Franco couldn't destroy this bust, rescued and kept hidden as a family secret for over 40 years.

Have a seat with the father of modern computing at this Manchester monument.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A local prank turned town icon.

One of Bristol's best-hidden gems has ties to Lord Byron, whence it became the nation's first reformatory school for girls.