An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

The upstairs reading room is packed with millions of rare books, literary manuscripts, and historical treasures.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

Free public park and gardens filled with peacocks and peahens.

A view-altering observatory at the University of Texas.

This eclectic, mosaic-clad home includes a bamboo ping-pong loft and a "Whispermaphones" intercom.

Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

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

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

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

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

Part bookstore, part café, and part forest.

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

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A kaleidoscopic warehouse-maze of handmade neon signs.

A pair of trees near a Hong Kong shrine are said to grant wishes, but only the ones they hold on to.

A colossal floating restaurant built to look like a ancient Chinese imperial palace.

This hulking behemoth is actually five interconnected towers built in the 1960s.