Why did the Nazis invade the Saarland?

After the First World War, Germany was economically and territorially weakened. Key to Hitler's aims was the rearmament of Germany to achieve Lebensraum and Grossdeutchsland. The Saarland was economically rich with extensive coalfields. It was also home to many German-identifying and German speaking people. The Saarland used to be part of Germany but was taken from them and given to France after the Treaty of Versailles. Therefore, the Saarland offered Hitler the chance to strengthen Germany's economy and also bring more Germans into the greater Germany. Another key policy of Hitler's was the destruction of the Treaty of Versailles, which the invasion of the Saarland allowed to do by annexing the Saarland from France back into German territory. This rearmament and expansion via the Saarland helped bring Germany closer to Hitler's vision: a great nation ready to conquer.