I just made the comment: "Hitler is rolling over in his grave" earlier today and it made me wonder if Hitler actually has a grave. I know his body was burned outside of the Fuhrerbunker, but was he formally buried anywhere else? Is there a plaque where his body was burned? Anything?
No, there is no grave or plaque. The Soviets buried some of the bits and pieces of what was left of Eva Braun, Hitler, and the Goebbels family they found in 1945 outside the Führerbunker in a KGB facility in East Germany until they left the country in 1970, at which point they burned the remains and dumped them in a local river. A more thorough investigation of the Führerbunker site in 1946 unearthed some skull fragments that were identified by the Soviets as Hitler's and they are still kept in Russian archives.
A grave or plaque would be unthinkable in today's Germany. There has been an information panel at the Führerbunker site that is designed to "counter myth building and nostalgic narratives".