The burial place of some of Mexico's most prominent residents is full of macabre stories and hidden masonic symbols.

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.

This strange sculpture of a menacing skull surrounded by sun rays was discovered at the foot of the Pyramid of the Sun.

The ruins of an ancient temple to the Aztec wind god discovered in the middle of a metro station.

The only castle in North America to ever house European sovereigns.

The famous artist couple lived and worked here, in two different houses separated by a bridge.

A church dedicated to the Mexican skeleton saint.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

66,000 pieces of art, donated by one of the world's richest men.

Superstitious? Discover the witchy side of Mexico through its largest esoteric market.

Frida Kahlo's childhood home, now a museum of her life and works.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

One of the first hotel rooms in a pod.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

Order “Proletariat’s Cutlet” at this communist-themed restaurant allegedly once visited by Lenin.

The final resting place of more than 200,000 people, this is one of the largest cemeteries in Europe.

This hidden collection of everyday objects illustrates life within communist Poland.

A statue honors the children who fought Nazis in Poland.

Warsaw's fantastically preserved gasworks...almost.

A couple turned their front yard into an artistic masterpiece.

One of the few remaining carousels built by master amusement park carver Charles I.D. Looff.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

These mysterious ancient stone spheres were created by a civilization lost to time and are now mostly lawn ornaments.