Death of President Hindenburg
Although his death didn't come as much of a surprise for the nation, but it was still quite significant to the circumstance the German "government" was in. When Hindenburg was still alive, Hitler could already act on whatever he wants to do, but he still has to take Hindenburg into consideration before he makes any major political moves. Now, with Hindenburg gone, he can act however he wants with no worries at all what-so-ever. So on 2 August, 1934, when Hindenburg FINALLY dies at the age of 87, Hitler immediately declares himself as the Fuhrer, or the sole leader. He also announced that as Fuhrer, he will add all the president's powers to what he already has obtained when he was the chancellor. He also forced an oath of loyalty from the SA to himself, every single soldier. To "show" that everything was done according to democratic elections and fair treating of parties (not), Hitler ran a public vote, or a plebiscite, that confirms to the people Hitler is their Fuhrer, and because of all the pro-Nazi propaganda, 90% of voters decided to favour this decision. Weimar Republic has now officially ended, and Hitler's Third Reich had begun.