The correct name for Truk is Chuuk State, but it is best known as Truk Lagoon, and is part of the Caroline Islands in the heart of Micronesia. Situated 965 km South-East of Guam and 5400 km South-West of Hawaii, it's unique barrier reef encloses one of the largest lagoons in the world, 64 km in diameter at the widest point. This protected expanse is dotted with twelve major volcanic islands, over twenty islets and countless coral cays and reefs. This combination of an atoll-like barrier reef and scattered volcanic islands has led to Truk being known as an "almost atoll".

The lagoon hosts diverse marine life. Over 500 species of corals and close to 1000 fish species are known in these waters.

Some of the bloodiest battles of WWII were fought in Micronesia. On February 17th and 18th 1944, the US navy launched a devastating air attack on the Japanese Imperial Fleet situated inside the sheltered waters of Truk Lagoon. The assault was fifteen times more powerful than the Japanese attack on Pearl Harbour. Code-named "Operation Hailstone" the initial strike was made up of 72 fighters launched from five carriers. When the smoke cleared, 15 Japanese naval ships, 6 tankers, 17 cargo ships, 25 American planes and 250 Japanese planes were lying on the bottom of the Lagoon. Subsequent air raids in April, May and June sunk more ships, and by the end of the war more than 60 destroyed vessels were on the Lagoon bed.

Truk's history of early Spanish domination was followed by German acquisition after the Spanish-American war about 1890, and then a Japanese mandate from the League of Nations upon Germany's defeat in 1918.

The Japanese era saw a great buildup of arms and bases in advance of a wide military blitz over the Western Pacific during WWII. The blitz was supplied heavily from facilities at Truk, where often more than 1,000 merchant and war ships moored in readiness for further deployment. Five airfields supporting close to 500 aircraft provided complete protection over Truk's Gibraltar-like facilities. A deep lagoon, high islands and circling barrier reef provided extensive natural protection. Patrol boats, torpedo boats, submarines, tugs, landing craft, gunboats and mine sweepers contributed to the final defenses and service needs to maintain this big base.

Truk was considered the most formidable of all Japanese strongholds in the Pacific. This reputation caused an overconfident Truk command to relax their vigil against invasion, in spite of U.S. forces fast approaching from the East. Supplies from Japan had almost ceased, due to immense successes of U.S. submarines equipped with torpedoes that found their mark. Supply convoys receiving nearly 90% losses enroute to Truk, deprived the garrison of food, fuel and new armaments desperately required to maintain strength.

By early 1944, U.S. forces had amassed a huge armada of top line carriers, battleships, cruisers, destroyers and submarines for a major surprise sweep against Truk on February 16th, 17th and 18th 1944. This attack, coded "Operation Hailstone", caught the Japanese totally unaware, and led to one of the most successful U.S. engagements of WWII.  After a follow up attack in April, 1944, Truk was reduced to rubble with over 70 shipwrecks, 400 aircraft destroyed or sunk, and the menace of this big fortress removed forever.

U.S. forces declined engagement with the 40,000 troops at Truk, and after these attacks, starvation consumed many of the defenders before the eventual surrender of Japan late in 1945.