Astronomers, making periodic observations of comets and their return frequencies, correlate the occurrence of meteor showers with the Earth passing through their orbital paths. Comets are a rich source of small particles that move faster than bullets. Most burn up in the atmosphere, but some persist and strike the Earth as a meteorite. Ancient people were puzzled by them. Mohammed is supposed to have placed one in a silver casing. A sizable meteorite from a 1514 German find was chained down so it would not fly back into the heavens. Native Americans sometime buried their dead with a meteorite chunk to act as a pass to heaven. Photos of downed trees from the 1908 impact site of the Tunguska meteorite in the Siberian taiga are shown. It is estimated to have been 2000 tons, but it has never been found. Every day, more than 10 tons of meteorites fall on the Earth, most as dust. A significant collection of meteorites has been assembled in the Moscow Meteorite Museum, part of the Academy of Science. Some are predominantly iron, while others are stony. In all cases, their composition does not differ from the same elements we have already characterized here on Earth.