Iceland - Geysir
The word "Geysir" comes from this location right here, in some unpronounceable national park in Iceland. A stop here was part of the Golden Circle bus tour I took. I'm sure my wife knows the name of the park (I'll have to update this later).
Seeing this Geysir, which spouted steam every 5 minutes or so, pockets of steam popping up throughout the park, and puddles of boiling liquid--it was eerie and cool. And it smelled a bit like rotten eggs.