The world's oldest known salt mine.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

The "feral child" who appeared in Bavaria in the 19th century remains as much a mystery as his unsolved murder.

A small but immensely extravagant palace built by the "Night King."

The fairy tale castle of the "fairy-tale king."

This strange statue features a bust of the famous composer plopped atop a woman's body.

This "thrice-cursed" island is allegedly home to Captain Kidd's lost treasure.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

This unique creation was made by the largest manufacturer of Christmas bulbs in 1946 to honor those returning from World War II.

At the right time of day, sunlight floods through the roof of this cave and illuminates the small pavilion hidden within.

This dazzling Buddhist temple was constructed from over one million ceramic tiles salvaged from a British shipwreck.

The headquarters of the Mahanikai school of Buddhism, Thailand's largest monastic order.

A white Buddhist temple with a golden restroom.

A unique sculpture park that specializes in the huge and bizarre.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

This historic old movie house was the scene of one of the Blob's most iconic attacks.

The residents of this ominous-sounding street in Pennsylvania liked its name so much they fought to keep it.

This giant disembodied horse head seems to balance impossibly on its nose.

A layered tribute to the work of mosaicist Isaiah Zagar.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.