The Medina Retractable Umbrellas
"...17m x 18m retractable umbrellas create the effect of a translucent vault, providing protection from the desert sun. At night, the umbrellas can be closed to promote the natural cooling of the court floor. These umbrellas have been in continuous service since 1992."
More umbrellas have been added over the years, covering the entire masjid's exterior marble floor.