Niagara National Historic Sites include Brock's Monument and Queenston Heights, the site of the Battle of Queenston Heights and the final resting place of Major General Brock, where visitors can climb 235 stairs for views or follow a self-guided tour covering the major scenes of the battle. Navy Hall survives as the last building of a former large military complex and key supply depot for British forts on the Upper Great Lakes; constructed in the 1760's, the Navy Hall complex was home to Lieutenant-Governor John Graves Simcoe, the Provincial Marine, and a mess for the officers of Fort George. Butler's Barracks, a ten minute walk from Fort George along the Otter Trail, has seen more than 170 years of continuous military occupation, beginning as a British Army depot beyond cannon range from the United States and later becoming a Canadian Militia training camp where many Canadians who fought in the Boer War, World War I, World War II, and Korea trained. Fort Mississauga, built by the British toward the end of the 1812 conflict, was intended to provide additional protection at the mouth of the Niagara River and to counterbalance Fort Niagara on the opposite American shore.