From StateImpact Texas:
About an hour’s drive outside of Sevilla, Spain’s old city, past grazing black-footed pigs and olive orchards, sits the Abengoa Solucar complex, and it’s truly a sight: Imagine cresting a hill and then all of the sudden seeing several large towers, over 500 feet high, with hundreds of beams of light striking them — solar rays from an army of mirrors arrayed in a circle on the ground below. They’re called heliostats.
“These heliostats are reflecting solar radiation toward the receiver that we have at the top of the tower,” says Valerio Fernandez, manager of the complex. The rays from the heliostats strike the top of the towers, like hundreds of magnifying glasses focused on one point in mid-air. The top of the tower shines so bright, you can’t look at it without sunglasses.