Monetary Union: Waiting to Exchange Money (July 1, 1990) People waiting to exchange money at the Sparkasse in Wanzleben (Saxony-Anhalt) on July 1, 1990. On this day, the State Treaty on the Creation of a Monetary, Economic, and Social Union (signed on May 18, 1990) took effect, making the Deutschmark (DM) the only acceptable form of currency in the DDR. Photo: Günter Zint.