Illustration depicting attempts to control the flow of lava from Helgafell, Iceland, in 1973. The lava flow threatened to inundate the port of Heimaey, so local volunteers pumped thousands of gallons of sea water onto the advancing mass. This was intended to hasten the cooling process of the lava, thus slowing it down and diverting the flow elsewhere. The attempt was only partly successful, but may have reduced the overall damage.