Although heavily fortified locations were not attacked in the War of 1812, the British managed to bypass or suppress the weak defenses at the mouth of Chesapeake Bay and burn Washington, DC. As a result, Congress approved a large-scale program of improved masonry forts, later called the third system of US fortifications, to replace the relatively small forts of the first and second systems. Newport was selected for one of the largest forts ever built in the United States, the new Fort Adams. Two other forts of the third system, Fort Monroe in Virginia and Fort Jefferson in Florida, were its only rivals in size in North America. Fort Adams' initial design was by French military engineer Simon Bernard, and the first 13 years of its construction were personally overseen by Joseph G. Totten of the Army Corps of Engineers, the foremost American fort designer. The fort was begun in 1825 and was first garrisoned in 1841, with construction continuing through 1858. A drawing in the National Archives shows that a similarly large fort in Jamestown on Conanicut Island, at the eventual location of Fort Wetherill, was considered but not approved. The new Fort Adams was unusual among American forts in having a tenaille and crownwork, plus a detached redoubt, protecting the fort on the landward side. These were designed to break up and channel an assault force, effectively forcing an attacker to resort to a long siege. In 1854 the fort was armed with 200 guns, and had positions for over 400. About 50 of these were 24-pounder flank howitzers, short-barreled guns for defense against an assault, mounted in casemates in the tenaille and redoubt.