Red blood cell order to stimulate production of red blood cells. Both practices are banned by the World Anti-Doping Agency. The first person to describe red blood cells was the young Dutch biologist Jan Swammerdam, who had used an early microscope in 1658 to study the blood of a frog. Unaware of this work, Anton van Leeuwenhoek provided another microscopic description in 1674, this time providing a more precise description of red blood cells, even approximating their size, "25,000 times smaller than a fine grain of sand". In 1901, Karl Landsteiner published his discovery of the three main blood groups—A, B, and C
U2 Live at Red Rocks: Under a Blood Red Sky U2 Live at Red Rocks: Under a Blood Red Sky U2 Live at Red Rocks: Under a Blood Red Sky is a concert film by Irish rock band U2. It was recorded on 5 June 1983 at Red Rocks Amphitheatre in Colorado, United States, on the group's War Tour. Originally released in 1984 on videocassette, "U2 Live at Red Rocks" was the band's first video release. It accompanied a 1983 live album entitled "Under a Blood Red Sky", on which two tracks from the film appear. The video was directed by Gavin Taylor and produced by Rick Wurpel and Doug