Revellers celebrate "Ash Monday" by participating in a colourful "flour war", a traditional festivity marking the end of the carnival season and the start of the 40-day Lent period until the Orthodox Easter,in the port town of Galaxidi, some 215 km (134 miles) north west of Athens, March 18, 2013. The revellers "fight" by throwing coloured flour, charcoal dust and powder painting until they essentially run out of supplies. (Photo by Yannis Behrakis/Reuters)

A woman wearing cut-off jeans and a halter-neck sun top in St Tropez, 1972. (Photo by Roy Jones)

The Royal Observatory just announced its Astronomy Photographer Of The Year 2013 winners. Australian photographer Mark Gee was chosen among a thousand amateur and professional photographers around the globe to win the top title. His work is part of an exhibition of the winning photographers, which opened on Sept. 19 at the Royal Observatory Greenwich. The Royal Observatory shared with us the winners and notable mentions of the competition. Their descriptions of the prizewinners can be found below the images.

Multicolored nets are set under olive trees to collect the olives on November 27, 2013 in Castagniers, southeastern France. (Photo by Valery Hache/AFP Photo)

Spanish surrealist artist Salvador Dali (1904–1989) viewing the camera through a magnifying glass at his home in Cadaques on the Spanish Costa Brava, 1955. (Photo by Charles Hewitt). P.S. All pictures are presented in high resolution.

A chimpanzee relaxes in the shade at the Safari Park as the popular attraction prepares for the upcoming Jewish festival of Pesach (Passover) on April 14, 2008 in Ramat Gan near Tel Aviv, Israel. (Photo by David Silverman/Getty Images)

Manuela Vargas at a dress rehearsal for “The Tigress of the Flamenco” given by her company at the Vaudeville Theatre, London. (Photo by Dennis Oulds/Central Press/Getty Images). 4th November 1964

Young Ian Archibald ponders the consequences of a complex critical study of beauty contestants during the Miss TV Times finals in London. (Photo by Central Press/Getty Images). 30 July 1971