The Spanish–American War of 1898 greatly increased the academy's importance and the campus was almost wholly rebuilt and much enlarged between 1899 and 1906. The ground on which most of the Academy sat was dredged from the surrounding bodies of water and consisted of silt. This was too fragile for the newer heavy stone buildings. Pilings were sunk from to deep. Some wooden with iron caps; modern ones of steel. Today's campus dates from that era. In 1905, Isherwood Hall, containing the Department of Marine Engineering, was constructed.