New aerial technologies, from drones to satellites, are revealing new mysteries. The famous pyramids of Giza appear to have been aligned to the stars. Satellite photos taken after Hurricane Katrina showed levees that were entirely swept away and helped rescuers find stranded people. An Indonesian volcano on Java burns a vivid shade of blue, and satellite images show the same colour in hydrothermal vents in the Danakil Desert, Ethiopia; both are burning sulfur gas. Salton Lake, California was created by irrigation, and irrigation carried agricultural pollution that eventually killed it.