Yves Klein, whose work is featured in the Virginia Dwan collection, is considered the most influential and controversial French artist to emerge in the 1950s. He is remembered above all for his use of a single color, the rich shade of ultramarine that he made his own: International Klein Blue. Klein’s highly eccentric symphony requires a 32-piece orchestra and 40-voice choir to sustain a D-major chord for 20 minutes, and then to sit, frozen in silence for 20 minutes.