Solar power tower heat demonstration. Hole melted in steel using the rays of sunlight focused by a solar power tower. The hole is 3 centimetres in diameter and was formed in seconds. Solar power towers are surrounded by mirrors that track the sun and focus its rays onto a receiver at the top of the tower. The receiver collects the sun's heat in a fluid which is used to produce steam to drive turbines to generate electricity. Temperatures achieved at the receiver range from 538 to 1482 degrees Celsius. Depending on its composition, steel melts at around 1370 degrees Celsius. Photographed at a German Aerospace Agency (DLR) facility in Cologne, Germany.