Truk was the biggest Japanese base in the South Pacific.  The raid in the papers was just the largest.  It was never invaded because Allied Planners felt it was too well defended to be taken without suffering unreasonable casualties among invading forces.  Instead, it was continuously bombed throughout the war and bypassed in the island hopping campaign.  It was not uncommon for planes bombing nearby islands to save a few and swing past Truk on their way home.  If I remember my numbers right the only place in the Pacific that had more tonnage of ordnance donated to it was mainland Japan.Here is a listing of the known shipwrecks in Truk Lagoon