Passage: The 1939 German ultimatum to Lithuania was an oral ultimatum which Joachim von Ribbentrop, Foreign Minister of Nazi Germany, presented to Juozas Urbšys, Foreign Minister of Lithuania on 20 March 1939. The Germans demanded that Lithuania give up the Klaipėda Region (also known as the Memel Territory) which had been detached from Germany after World War I, or the Wehrmacht would invade Lithuania. The Lithuanians had been expecting the demand after years of rising tension between Lithuania and Germany, increasing pro-Nazi propaganda in the region, and continued German expansion. It was issued just five days after the Nazi occupation of Czechoslovakia. The 1924 Klaipėda Convention had guaranteed the protection of the status quo in the region, but the four signatories to that convention did not offer any material assistance. The United Kingdom and France followed a policy of appeasement, while Italy and Japan openly supported Germany, and Lithuania was forced to accept the ultimatum on 22 March. It proved to be the last territorial acquisition for Germany before World War II, producing a major downturn in Lithuania's economy and escalating pre-war tensions for Europe as a whole.

Question: What territory did the Nazi occupy?
Czechoslovakia