Just inland from lakefront Coronation Park, the sight of Fort York National Historic Site (toronto.ca; free) amid 17 grassy hectares, with the CN Tower and skyscrapers looming behind, is a curious snapshot of Toronto's identity today. Established by the British in 1793 to defend the then town of York, the fort was rebuilt after being almost completely destroyed during the violent Battle of York in 1813, when American troops defeated a force of Ojibwe and British fighters. It remained in military use until the early 1930s. Visitors can wander through the site's scattered structures; free 45-minute guided tours run hourly. Each June as part of National Indigenous Peoples Day in Canada, Fort York is the setting for the Na-Me-Res Pow Wow & Indigenous Arts Festival (nameres.org).
The visitors center has a museum relating the history of the site and showcasing period artifacts. It also has a small theater where an orientation film is screened. The fort is open year-round; check the homepage for special events and tour details.