The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

While the U.S. and Soviet Union were engaged in a space race, Poland built a UFO on the ground.

One of the world's first dedicated bank buildings in the world is now the oldest one.

Stockholm's deepest subway station is also a stunning ecological wonder.

Now a hotel, this former bank was the site of a robbery that spawned a psychological phenomenon.

Inside this church, a monument honors the first burial site of the famed philosopher.

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

Stockholm's narrowest alley is barely over two feet wide.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

The library's graceful rotunda is like a bibliophile's temple.