Geysir and Strokkur are two of the most famous geysers - hot springs that erupt periodically - in Iceland.

They lie in a geothermal region in the Haukadalur Valley near the Hvíta River, in the southwestern part of the island. The two geysers are located near Mount Hekla, an active volcano.

Geysir

Geysir is also known as Great Geysir

The name "Geysir" means "gusher" in Icelandic. The word "geyser" has come to describe all similar geothermal fountains.

In 1810, Geysir erupted at 30-hour intervals.

By 1815, it played every 6 hours for up to 15 minutes, pushing up several jets of water at once.

In 1916, the eruptions stopped.

In 1935, they began again after a channel was dug around the edge of the Geysir's vent.

Since then, Geysir's level of activity has been inconstant. It sometimes goes for year with erupting.

When Geysir erupts, it can send boiling water and steam up to 70m (230ft) high.

Strokkur

Strokkur erupts every five to ten minutes, much more frequently than Geysir.

When Strokkur erupts, the shaft of steam and boiling water that is produced can reach up to a height of 20m (70ft).