When Britain declared war on Germany in 1939, Australia also entered. During the war, Sydney experienced a surge in industrial development to meet the needs of a wartime economy. Far from mass unemployment, there were now labour shortages and women becoming active in male roles. Sydney's harbour was attacked by the Japanese in May and June 1942 with a direct attack from Japanese submarines with some loss of life. Households throughout the city had built air raid shelters and performed drills.