The final resting place of the world's first nuclear reactor.

A group of college students hauled a desk up a mountain more than 40 years ago. The notebooks inside have become a makeshift time capsule.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

This lookout tower built in the 1930s is now an in-demand cabin with what might be the best view of the Seneca State Forest.

The building features one of the last remaining free-floating spiral grand staircases in the U.S.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.

For one day every month Barcelona's Estació de França transforms into a market for model trains.

North America's largest accredited model railroad museum.

Inside this old train depot resides a multi-line model train covering western North Carolina.

This delightful attraction features over a dozen miniature train layouts which you can operate and interact with.

A model train wonderland hidden beneath Gare de l'Est station.

A comprehensive collection of toy and model trains, largely from the mid-20th century.

The fictional star of "Breaking Bad" is memorialized with a real-life gravestone in his hometown.

How did a massive marine arthropod find its way to landlocked Ohio?

Order cookies baked by cloistered nuns in a 400-year-old monastery.

This lucky bronze frog was gifted to Madrid by a casino.

An ancient Egyptian temple in the middle of Madrid, Spain.

A lush indoor jungle fills this bustling Madrid transportation hub.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.