Masada.

Masada is a 1981 American historical drama television miniseries aired on ABC under the tentpole ABC Novel for Television. The screenplay by Joel Oliansky is based on Ernest Gann's 1971 novel The Antagonists. A dramatization of the historical siege of the Masada citadel in Roman Palestine by legions of the Roman Empire in AD 73. A siege that ended when the Roman armies entered the fortress, only to discover the mass suicide by the Jewish defenders when defeat became imminent.