The bases were built to support the island hopping Pacific War efforts of the allied nations fighting the Empire of Japan.
At the start of World War I in 1914 British warships destroyed the German colonial plantation owner's radio station.
The United States Army Air Forces bombed the Truk base, but it was bypassed in the amphibious landing war.
The US Navy survey ship USS Sumner found the lagoon was well protected and usable for fleet anchorage.
Truk was attacked by air and had its supply lines cut off by sea, called Operation Hailstone.