If you're into historic places the big peninsula of peloponnes just west of Athens might be a place to visit. It have historic places like Olympia, where the olympic torch are lighted, the enormous amphitheater of Epidaurus, the ancient ruins of Mistras just to mention some. And there is also very beautiful beaches there. Voidokilia beach is very nice and special. And on the way from Athens you will pass the chanel of Korith