These bluffs commanded the Hudson River and the valley below, General Burgoyne's only route to Albany. Although the valley here was wide, in 1777 a huge swamp called the Great Vly clogged the approaches from the north, forcing the British Army to stick to the river and the road. Gates ordered the construction of defenses here on the recommendation of Colonel Tadeusz Kosciuszko, a young engineer from Poland. Sent by Gates on September 11 to find suitable ground for a defensive line, Kosciuszko quickly recognized the defensive possibilities on Bemus Heights. Military engineers under his orders planned defenses that used every advantage of the terrain, and construction began the next day, just one week before the first battle.