A group of school children observe an untitled work made of pure intense ultramarine pigment, part of the exhibition of French artist Yves "Monochrome" Klein, at the Guggenheim Museum in Bilbao, northern Spain, February 1, 2005. The exhibition, a retrospective of the brief but intense career of the influential French artist, began Tuesday and runs until May 2nd. Pictures of the month February 2005 REUTERS/Vincent West VPW/PH/AA