Probably after the Anschluss. Although Hitler had already violated the Treaty of Versaille by rebuilding Germany's military and moving troops into the Rhineland, the annexation of Austria was the first big territory takeovers and as a result of the Allies inability to punish Hitler for this violation of the Treaty of Versaille, it allowed him the momentum to quickly overtake Lithuania, Bohemia, Moravia, and Czechoslovakia. Which of course leads up to the invasion of Poland.
Scientists believe that Mashkan-shapir's collapse was caused in part by destruction of the fields by mineral salts. When mineral salts concentrate in the upper levels of the soil, it becomes poisonous for plants. In Mesopotamia, irrigation was essential for crop production.
The emancipation proclamation issued by president Lincoln freed all of the slaves in the United States during the Civil War--although many remained enslaved illegally in the South.
