In the original Assassin's Creed, Altaïr visits Acre to assassinate William of Montferrat.
Acre is one of the three major cities in the game's Holy Land setting, alongside Damascus and Jerusalem. Altaïr's mission takes place in 1191, during the Third Crusade, and targets William, the Templar-affiliated regent of Acre.
The game presents Acre as a fortified coastal city with Crusader architecture, crowded markets, rooftops, and a large harbor district. William's assassination is one of Altaïr's early targets after Al Mualim reduces his rank and equipment.
A common mix-up is Damascus, because it is also a major investigation city in the same game. Damascus is the setting for Altaïr's assassination of Tamir, while Acre is associated with William of Montferrat.