Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

It houses the remains of a 17th-century version of the Titanic.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

The world's first ice hotel is still one of the most elaborate and beautiful.

WWII artifacts, including the building itself.

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.

The tallest freestanding structure in the United Kingdom.