Nature

The world's first and only natural nuclear reactor.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

A desert in southeast Asia, complete with a beautiful lake covered in lotus flowers.

A volcanic fissure over two miles long and up to 70 feet deep.

A surviving remnant of the thick ice mass that once mantled most of Western Canada's mountains.

A hundred and twenty year old twelve story lighthouse located on a beautiful Indonesian island.

Mysterious rocks that ring musically when struck.

The only road through the heart of Glacier National Park.

Two rocks in a perpetual kiss and one of "the most romantic spot in America."

Every year, over 25,000 monarchs overwinter in Pacific Grove.

Webcam that broadcast the hatching of Bald Eagles to millions of viewers.

A 10 million-ton rock once worshiped by the Tahamies Indians, accessed by an astounding staircase.

Part of one of the largest flooded cavities on the planet, and littered with prehistoric animal bones.

Gigantic Romanian salt mines used to heal respiratory conditions.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Underwater volcanic eruption forms new island off the coast of Tonga.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

One of Chile's most active volcanoes is riddled with beautiful caves.