Where was Caesar assassinated?

Caesar has gone to the forum- a public place of government- to accept a petition, but he is taken to a room past the Theatre of Pompey. The exact location is said to be Campus Martius. It is on a false pretense of having Caesar read the document which is discovered to be fake.

So in a room past the Theatre of Pompey, on the Ides of March, 44 BC, Caesar is tricked and betrayed.  He fights back valiantly, but soon realizes that his trusted Brutus is among his attackers.  He utters the famous line, "Et tu, Brute--then fall, Caesar."  He falls and is dead.