1. Night of the Long Knives - happened in 1934, it was a series of politically motivated murders.
2.Wannsee Conference - happened in 1942, concerned the final solution
3.Auschwitz opens - in 1940
4.Kristallnacht - happened in 1933, it was a night of Anti-semitic attacks and arrests
So the order is 4, 1, 3, 2