Inside an old airplane hangar, friends and strangers alike play on a massive trampoline.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

Tiki luxury on Nob Hill.

A huge musical instrument played by the ocean.

A psychedelic labyrinth on the San Francisco bay.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

A 12th-century fortress containing some of Berlin's oldest buildings.

Solar observatory doubles as a daring display of Expressionist architecture, much to Einstein's chagrin.

A quaint Russian village in the middle of a German metropolis.

Germany's Glienicke Bridge has a shady history of clandestine meetings, espionage, and spycraft.

The "Prussian Versailles" that is as glorious today as when it was built.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

An abandoned hotel in the highlands of Bali is shrouded in stories of ghosts, curses, and corruption.

The steepest classic funicular in the world glides along a dizzying incline.

In this truly magical place, rent hasn't been raised since the year 1520.

Perhaps the tiniest sculpture in Saint Petersburg is a little bronze finch inspired by a song.

A serpentine highway twists and turns over the treacherous Norwegian Sea.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

Gorgeous views of Italian mountains and valleys form the backdrop of this unique open-air theater.

A whimsical village of unique treehouses resides in a Washington forest.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

At the United Kingdom's only residential library you can sleep among the books.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Mirrored floors and arched shelves create the illusion of an infinite tunnel of books.