Beginning in late March 1945, Allied forces began discovering these hidden repositories in what would become the "greatest treasure hunt in history". In Germany alone, U.S. forces found about 1,500 repositories of art and cultural objects looted from institutions and individuals across Europe, as well as German and Austrian museum collections that had been evacuated for safekeeping. Soviet forces also made discoveries, such as treasures from the extraordinary Dresden Transport Museum. Hundreds of the artifacts were surrendered by, or had their locations reported by, SS General Karl Wolff as part of Operation Sunrise, his secret negotiation with the Office of Strategic Services. These included the contents of the Uffizi and Pitti palaces and paintings by Titian and Botticelli.