The Arctic Circle runs through this isolated spot north of Iceland.

Iceland's largest geothermal mud pool is a little bit haunted and a little bit dangerous.

One family's mission to exemplify sustainability took on a whole new life as a surprisingly beautiful home.

Modern design and unusual architecture make this mountaintop temple no ordinary Buddhist retreat.

Colorful umbrella-covered trees in Singapore's Little India look straight out of Dr. Seuss.

This mysterious underground cave in Shropshire dates back to the 18th or 19th century.

The island of Lanai in Hawai'i is a paradise for cats and cat lovers.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

A sobering account of the vibrant multicultural neighborhood that was destroyed under apartheid.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

The world’s first hotel to be run by robots.

A psychedelic labyrinth on the San Francisco bay.

It took over 100 years to decode this enigmatic epitaph for two buried brides.

This lake in the Cascades lives up to its name, disappearing down a hole every spring.

Natural time capsule containing an alien ecosystem.

The Grand Canyon of Texas.

This frozen tunnel in central Alaska is both an engineering feat and a valuable climate classroom.

A 70-foot-deep ice cave formed by lava from Mt. Fuji on the edge of Japan's "Suicide Forest." 

Visitors flock to see this church tower's unintended feature: It happens to resemble a giant chicken from multiple points of view.