Mars Hill, or as it is also known, Areopagus, is a bare marble hill next to the Acropolis.
Near the base of the stairs is a bronze plaque with the Greek text of Paul's sermon. Your guide can translate this for you while you are there. At the top, there is an exceptional view of the Acropolis.
According to Greek mythology, Ares (the god of war, known to the Romans as Mars) was on trial and tried here (by the gods) for the murder of Poseidon's son, Alirrothio. Later, in classical times, the Areopagus functioned as the primary court of Athens for murder cases.
NOTE: Ne careful walking as unfortunately, its ancient marble steps are quite smooth and slippery from all the elements over the eons of times.