A giant time capsule not scheduled to be cored until 2040.

Once damaged by Hurricane Agnes, this bridge is now on the National Register of Historic Places.

The world's largest indoor go-kart racetrack is hiding in Connecticut.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

The first skyscraper to include a Ferris wheel built into the facade.

One of the last doorless, continuously moving elevators still in use in the U.K.

The "plyscraper" is the world's tallest building made predominantly out of wood.

The world's tallest circular building is loaded with symbolism, but many just see a big donut.

A tropical rainforest designed to resemble a scene from the monumental film.

This bathhouse includes an option to soak in radioactive water.

After a profound show of devotion for his master, a dog becomes the symbol of loyalty for an entire nation.

Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

Fire meets ice at the southernmost volcano on Earth.

The home of half the world's population of critically endangered mountain gorillas.

A hiking/biking/exploring trail that winds across over 140 miles of Rwandan shoreline.

Indiana's oldest sternwheel paddleboat has been plying the placid waters of Webster Lake for 90 years.

This historic estate on the east shore of Lake Tahoe was home to an eccentric millionaire (and his pet elephant, Mingo).

This small island was the first National Wildlife Refuge ever created in the United States.

Mount Nyiragongo has erupted at least 34 times since 1882 and is home to the world's largest lava lake.

At night, bats patrol this magnificent 18th-century space in search of book-eating pests.

These roaring primates were considered a divine creature in the cosmology of the Maya.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

A patch of Philippines forest devoted to saving the lives of an emotionally sensitive species of googly-eyed primates.

This research center for rare prosimians is studying how they sleep to help prolong human life.