"History" is the noun , I think you know what 'history' is ?!
'historical' is an adjective and refers to whatever associated with history and past events .
The historical site , historical facts, historical event ect..
"historic " is also an adjective and means ,that something is famous and important in history ,historically significant .
Buildings, landmarks ,monuments are called historic because of their significance .They are also historical because their relation to history .