Meant to be one of the most extravagant hotels in the world, now an eerie, abandoned architectural gem in Mexico City.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

Twelve natural mummies are displayed in the crypt of this former monastery school.

A church dedicated to the Mexican skeleton saint.

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

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

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

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

Part bookstore, part café, and part forest.

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

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

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

From Iggy Pop to David Bowie to Nick Cave, this regal music studio has served some of the all time greats.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

A collection of abandoned typographic signs from Berlin and beyond.

This classic restaurant features a gorgeous mirror-clad room.

The most visited, and possibly most controversial, museum in Germany.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.