Strokkur (Icelandic for "churn") is one of Iceland's most famous geysirs, erupting regularly every 4-8 minutes. Strokkur has a long history of activity, beginning in 1789, after an earthquake unblocked the plumbing system of the geyser. It continued to erupt until 1896, when another earthquake blocked the conduit of the geyser. Then in 1963, locals cleaned out the blocked conduit and the geyser has been regularly erupting ever since.
Geysers are temporary geological features, associated with volcanic areas; there are over 1000 known geysers in the world, half of which are located in Yellowstone Park.