Brock's Monument is a 56-metre column atop Queenston Heights in Queenston, Ontario, Canada, dedicated to Major General Sir Isaac Brock, one of Canada's heroes of the War of 1812. Brock, a British Army officer in charge of defending Upper Canada from a United States invasion, and one of his aides-de-camp, Lieutenant-Colonel John Macdonell, are interred at the monument's base on the heights above the battlefield where both fell during the Battle of Queenston Heights. The current monument was constructed between 1853 and 1856, which replaced an earlier Monument to Brock on the battlefield. Parks Canada maintains the monument, the most imposing feature of Queenston Heights National Historic Site. It is the fourth oldest war memorial in Canada.