Dikili Tash is one of the oldest archaeological sites in eastern Macedonia, a low tell where layers of Neolithic, Bronze Age, and later settlement sit close to the road between Kavala and Drama. It will not give you the instant drama of Philippi's theatre or basilicas, but it adds a much deeper time scale to the plain: people were farming, storing food, and making pottery here thousands of years before the Roman city took shape.
Come for context rather than spectacle. The site is best for travellers who like archaeology in the ground, with the imagination doing part of the work, and it pairs well with the Philippi ruins and archaeological museum. Check access locally, since research sites can have limited interpretation and irregular visitor arrangements.