Photo feature: Mayor Rahm Emanuel (center, podium) speaks at the base of Pablo Picasso’s untitled sculpture in Daley Plaza Tuesday afternoon in a ceremony marking the iconic public artwork’s 50th anniversary overlooking the plaza. The Spanish artist is reported to have turned down payment for the piece meant to enhance the newly built Chicago Civic Center, the original name of the Daley Center. The landmark piece was unveiled on Aug. 15, 1967 by then-Mayor Richard J. Daley, telling the surprised crowd, &ldquo …