I'm not doing it by the book. Instead of descending feet-first, I am spread-eagled and trying to make out the two massive wrecks that lie in more than 30 meters of water below me. Exhaled air pulses past my ear. A mercury- silver bubble is trapped under my mask as I fall through the water.
Shadows take on sharper lines as I descend into the murky gloom of Guam's Apra Harbor, until the relics of two world wars are discernible on the sandy bottom, their towering masts and bridges covered in a half-century of marine growth.
The German-flagged SMS Cormoran was the first to settle here, half a world away from where she began her life as merchant raider. She came to rest listing to starboard after her captain blew a jagged hole in her bottom rather than hand her over to the United States authorities on Guam April 17, 1917, the day that America entered the war.