A Geyser called Geysir

Iceland is located on the tectonic plates, and is essentially one big volcano.  Because of this, there's a whole host of interesting geology.

Here's an actual fault in the ground, with magma!  Ok, the magma isn't real, but the fault is, opened up by a recent earthquake.

The geologic activity creates all sorts of awesome geology.

There is a lot of tectonic activity in Iceland, and in some places, the ground is still steaming, smelling of sulfur.  In fact, in Icelandic homes and hotels, there are no hot water heaters.  The hot water comes directly from the ground, geothermally heated and mixed with cold water to reach the right temperature.  That means every time you shower, you end up smelling like sulfur, but at least you don't have to worry about your husband using all of the hot water!  (If he does use all of the hot water in Iceland - that might be a significant problem.)

Clouds of sulfur rising from the ground in Iceland

We traveled to a geyser called Geysir.  All other geysers get their name from this Geysir... a true trailblazer.  It's been erupting off and on for the last 10,000 years, sometimes erupting quite often, other times only erupting sporadically.   Sometimes, especially during an earthquake, Geysir would erupt up to 120 meters in the sky for hours at a time.  Sometimes the eruptions were powerful enough to shake the earth itself.      

Pools of geothermally heated water under the Icelandic sunset, in now dormant geysers. 

Geysir now erupts once about every 6 minutes, which makes it very easy to photograph. 

Geysir sits, tourists at the ready to photograph it when it goes off!

The eruption begins. Note the sphere of water and it's unique aqua color!

There it goes!

After the eruption, water rushes in to the now vacated chimney. 

Nearby Geysir, we meet some of the locals, the weather-hardened ponies of Iceland.

And for a point: some Icelanders for a long time threw something into a dormant geyser in a nearby town.  When the geyser went off, it spewed what they had thrown inside it all over the town.  What did they throw in the geyser?