Shortly before 8 am on Sunday, December 7th, 1941, Japanese aircraft carried out a surprise attack on the American Fleet based in Pearl Harbor in the Hawaiian Islands. In just 90 minutes the Japanese Navy managed to destroy seven battleships, around 90 support ships, and 250 aircraft, with a total of some 5,000 servicemen wounded or killed. The next day the United States declared war on Japan, officially entering into World War II. Over more than three years, a series of attacks were carried out by the United States against the bases of Japan in the Pacific, finally leading to its final attack on Japan. Today, divers can revisit the historic battle site of Operation Hailstone in Truk Lagoon, in Micronesia. 

Truk Lagoon was occupied by the Japanese since World War and completely unnoticed until a reconnaissance flight in 1943 by the Americans. At this tiny atoll was, in fact, the largest Japanese naval base in the entire Pacific. The United States entrusted to Task Force 58 to plan and execute an attack on the Japanese fleet. Five heavy aircraft carriers and four light carriers, provided a platform for launching more than 500 attack aircraft onto Truk Lagoon. Having seen the recon plane, the Japanese Combined Fleet transferred most of the naval fleet to Palau and other Japanese bases leaving the atoll was almost undefended. The first wave of American bombers sunk anchored ships with bombs and torpedoes. The second wave destroyed the infrastructure, such as fuel bunkers and munitions arsenals. Most of the vessels moored in the lagoon were sunk and two-thirds of the Japanese aircraft were destroyed. The island airstrips were rendered unusable. For the surprise and magnitude of the attack that killed over 5000, many historians describe Operation Hailstone today as the “Japanese Pearl Harbor“.