Marathon's main draws are its ancient battlefield sites and the excellent Archaeological Museum. The Tumulus of Marathon — the burial mound of the fallen Athenians — is the most evocative site, a quiet grassy dome on the coastal plain where the battle was fought. The beach at Schinias makes a natural end to a history-focused visit. The area can be covered in a comfortable half-day from Athens, or a full day if you add the ruins at Rhamnus to the north.