During the American Revolutionary War (1775–1783), the park was a site of the Battle of Long Island (aka Battle of Brooklyn). American forces attempted to hold Battle Pass, an opening in the terminal moraine where the old Flatbush Road passed from the villages of Brooklyn to Flatbush. It fell after some of the heaviest fighting in the engagement, and its loss contributed to George Washington's decision to retreat. Even though the Continental Army lost the battle, they were able to hold the British back long enough for Washington's army to escape across the East River to Manhattan. Plaques north of the zoo, as well as the Maryland Monument at Lookout Hill's foot, honor this event.