The world's largest drain sits below the city of Kasukabe, Japan.

Enormous underground chamber built to detect 'ghost particles' of the universe.

Open-air museum with an elaborate sculpture garden, stretching for over 70,000 square-meters.

This spa theme park lets its guests take a dip in pools of coffee, wine, or ramen broth.

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

Hanging over one of Japan's "hidden valleys," these vine bridges must be remade every three years.

Bioluminescent firefly squid light up this Japanese fishing port.

The oldest hotel in the world has been operated by the same family for over 1,300 years, even catering to samurai.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

A natural gas leak provides a flickering flame beneath a waterfall.

Once the most densely populated place in the world, this island is now a ghost town.

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

A taste of the macabre Tokyo's ritzy shopping district.

The atmospheric road was never meant to be so creepy.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Fine dining in the bizarre world of Lewis Carroll.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

This lab's maddening silence is good for business but bad for sanity.

Rising from the sea like a stone monster.

An isolated dive site teeming with cnidarians.

A battle between nature and architecture in the Cambodian jungle.

Monasteries on rock pillars, once accessible only by frayed ropes.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.