This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.

There's something big lurking beneath the surface of this tiny Oregon park.

This one-time health resort was used by aristocrats around the world.

Contains a wealth of information about the first exploration and later use of the Green and Colorado Rivers.

This set of three large, volcanic hot springs is a favorite haunt for intrepid divers.

Erosion and various mineral deposits give this striking canyon its distinct color and soft appearance.

A small oasis not far from downtown Moab.

An Ancestral Puebloan ruin that appears to burst into flames in the sunlight.

One of the world’s largest collections of petroglyphs records 2,000 years of human activity.

A tunnel with windows, so you don't miss out on the impressive views.

The most northern place on the mainland of Great Britain.

This site contains overlapping ancient graveyards that existed about 1,000 years apart.

This narrow coastline trail through the dense Kauai wilderness is among the most beautiful and dangerous in the world.

A tunnel of hardened lava along Maui’s famous Road to Hana.

This black shoreline is made up of exploded lava particles.

This tiny square mile of Canadian sand was once considered the world's smallest desert.

A tiny wilderness cemetery commemorates the deadliest episode of the Klondike Gold Rush.

The northernmost international land border crossing in the United States.

Home to a timed geyser created by complete accident.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

A red-brick beacon stands against the tempestuous Atlantic, on the windiest site in the United Kingdom.

The sign marks one of the endpoints to mainland Britain's longest overland travel route.

A cemetery full of touching tombstones from a community of railroad workers, uranium miners, and Cold War missile launchers.

The world's first nuclear power plant is open to visitors looking to role-play a meltdown.