The Navy Yard was a busy center in the 19th century and was important in the development of the area. The lively wharf was a center for jobs, serving ships with lumber and raw materials for the growing city. It also played a key role in defending the city from the British during the War of 1812. Surrounding the wharfs was a large commercial district, light industrial businesses, and one of the city’s most notable neighborhoods. As the city and nation developed, the Navy Yard changed from ship building to making finished ship products and weapons ammunition. By the mid-1940s in wartime the Navy Yard and the expanded Annex area were making the most ammo with 26,000 employees in 132 buildings on of land.