A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

Eat a Nobel banquet from any year in the basement of Stockholm's City Hall.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

Early habitat dioramas and home of the elusive gaff, the skvader.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

These Finnish rapids have been attracting tourists for over a hundred years and are now released with the push of a button.

More than 200 eclectic sculptures surround the artist's home.

The etchings on this narrow channel between two islands bear witness to maritime travelers who have passed through since the Middle Ages.

A little-known sculpture park of contemporary environmental art in a Lapland forest.

Crawling into this primordial cave may feel disconcertingly familiar.

A collection of collections ranging from dentistry to minerals.

A lovingly curated curio shop in which the taxidermy wear newspaper party hats, and peanut shells are spread across every surface.

Legend has this precariously placed rock was placed by giants. Science has another explanation.

Ancient man-made caves underneath small town Belgium.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

The former home of a trailblazing surrealist is still filled with haunting dolls and grim paintings.

Explore 400,000 years of humans' "battle against darkness" in this offbeat but thorough lamp museum.

A visionary precursor to the Internet made of index cards.

The Belgian library displays burned books that were salvaged from the fires of both world wars.

A wonderfully kitsch bookstore the size of a supermarket.

The bronzed skull of a beheaded traitor was affixed to the city gate in the 17th century.

Descend into the tunnels to experience the life of a coal miner.

An open-air sewer system that was covered piece-by-piece over 300 years.