Riverdale Park, which now sprawls across 104 acres and is bisected by the Don Valley Parkway and Don River, has a layered past. In 1856, the City of Toronto purchased the 48 hectares east of the Don River for the construction of the Don Jail. Riverdale Park officially opened in 1880 on the west bank of the Don River, led by Mayor James Beaty and Henry Scadding, an early historian of Toronto. By the early 20th century, however, the eastern half of the park was turned into a landfill. To this day, you can still observe the green posts along the edge of Riverdale Park East, which are actively releasing the gas from decades-old landfill beneath your feet.