National Geographic

THEY ARE WATCHING YOU 49``````In the 1960s the U.S. Army Corps of Engineers built more than270 concrete crosses, 60 feet wide, in the Arizona desert.7KHNQRZQGLPHQVLRQVKHOSHGFDOLEUDWHWKHZRUOGŠVƃUVWVS\satellites. To create the image above, two artists photographedthe cross, tracked the trajectories of satellites that passoverhead, and drew arcs in the sky showing their paths.-8/,($1$1'$1''$0216$8(5``````SATELLITESWATCHING