In and around the constellation Virgo, astronomers have located several thousand galaxies belonging to the Virgo cluster of galaxies. It is the nearest large cluster of galaxies. Several of the brighter ones can be seen with the help of an amateur telescope, but none are visible to the naked eye. The brighter galaxies were listed in the catalog drawn up by the 18th century French astronomer Charles Messier, and are identified by 'M' before the catalog number.