The world's largest model of our planetary system.

Part of an abandoned19th-century fortress hides in plain sight inside a modern office building.

This abandoned lighthouse looks like a rusting oil rig, but has managed to survive a number of storms.

A floating underwater hotel, created by a Swedish artist.

A Stockholm metro station is home to an escalator that is not only the longest in Sweden, but among the longest in the world.

The remains of Alfred Nobel's first nitroglycerine factory can still be found on the shores of a Swedish bay.

This Stockholm light tower can be controlled by anyone with a smartphone.

Sound travels strangely in this underground whispering gallery.

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

Frequent fliers welcome in this airplane hotel.