Tonotan Heavy Artillery Caves

During World War II, the Imperial Japanese Navy made Chuuk its combined fleet base for nearly two years. It fortified natural caves like this throughout the islands, often installing guns and even railroad tracks to haul munitions and supplies. After the major American air attacks of 1944—which killed or wounded over 4,000 Japanese and 120 locals—the lagoon’s wrecks have gained renown worldwide among divers. But the terrestrial sites remain unexploited and often untouched, as they are slowly reclaimed by the jungle.

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