Surtsey (Icelandic, meaning "Surtur's island") is a volcanic island off the southern coast of Iceland. At it is also the southernmost point of Iceland. It was formed in a volcanic eruption which began 130 metres (426 ft) below sea level, and reached the surface on 14 November 1963. The eruption lasted until 5 June 1967, when the island reached its maximum size of 2.7 km (1.0 sq mi). Since then, wind and wave erosion have caused the island to steadily diminish in size: as of 2002, its surface area was 1.4 km (0.54 sq mi).
The new island was named after Surtr, a fire jötunn or giant from Norse mythology. It was intensively studied by volcanologists during its eruption, and afterwards by botanists and biologists as life forms gradually colonised the originally barren island. The undersea vents that produced Surtsey are part of the Vestmannaeyjar (Westmann Isles) submarine volcanic system, part of the fissure of the sea floor called the Mid-Atlantic Ridge. Vestmannaeyjar also produced the famous eruption of Eldfell on the island of Heimaey in 1973. The eruption that created Surtsey also created a few other small islands along this volcanic chain, such as Jólnir and other, unnamed peaks. Most of these eroded away fairly quickly.