This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

Eighty million natural history specimens call this gargantuan museum home.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

This volcanic cave lake is essentially hard proof that Iceland is the most magical place on Earth.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

This semi-secret storybook hedge maze is also the oldest garden in the city.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

Experience park where visitors are told to expect the unexpected.

This geothermal hot spring hides beneath a slowly growing mineral dome.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

An acoustic anomaly with a mysterious cause.

This massive wooden building contains a giant Buddha, healing pillars, and tame deer wandering the grounds.

The magical, mossy forest that inspired 'Princess Mononoke.'

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

The largest self-built castle in the U.S., six decades in the making.

A modernist landscape of water and sci-fi concrete.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A lush green oasis in the middle of Chicago.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The world's longest known cave system.

Each year these high desert hills are absolutely covered with poppy flowers in a surreal show of nature.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

This naturally-sourced hot spring is now home to a clothing-optional resort.