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.

Twenty-six years later, imperial Japan’s Tokai Maru was riding at anchor in the lee of the port’s breakwater and almost directly above the Cormoran when an American submarine fired a salvo of torpedoes from the mouth of the harbor. The Tokai Maru was a large armed freighter, some 150 meters long, and she sank quickly. Her bows are still scarred by the force of the explosion that dragged her to the bottom.

The Japanese vessel came to rest with her keel touching the Cormoran’s stern, close to her rudder and propellers. A diver can, perhaps uniquely, bestride these two relics of the most destructive conflicts of the last century.

It is relatively straightforward to descend to the Tokai Maru and the Cormoran, and an over-swim gives divers a good impression of both their scale and what they looked like before they were sunk. Entering either vessel, however, is a different proposition altogether.

Wreck-diving is a specialized art and requires training and planning. Sunken vessels can be unstable, disorienting and prone to silting up, so formal qualifications in wreck-diving and diving with local operators who know the site are a prerequisite. More than one diver has died on the Cormoran.

Despite the build-up of rust and sediment, the interior of the Tokai Maru is recognizable for what it once was. Heavy doors stand open on their long-unused hinges and light filters through twisted beams to illuminate the bridge and a tiled bathroom. The slightest careless flick of one of my fins stirs up small clouds of revolving silt.

The holds of the Cormoran (which is rated as an advanced dive site) are deep and empty, but a room off one of the passageways still holds an old-fashioned bathtub complete with lion-claw feet. Most of her portholes have been scavenged but the ship is now protected by law from artifact-hunters.

Not surprisingly, thousands of fish have made the harbor’s wrecks their own. Schools of fusiliers and colorful butterfly fish dart away from divers, although the more aggressive triggerfish tend to dislike humans intruding into their world — and can draw blood. There are also a number of sharks living in the harbor, including hammerheads, although they generally shy away from divers.

One of the fishes’ favorites is the cavernous Kitsugawa Maru, another victim of World War II. Air-strike records indicate that the Japanese freighter was hit at least six times amidships and eventually sunk by aircraft-launched torpedoes. Today, her forward mast and bow area (complete with cannon and corroded, unstable ammunition) are draped in multicolored coral that make spectacular viewing on a night dive.

The needle on my air gauge is approaching the red zone so I follow my bubbles as they lazily ascend, tumbling over one another until they break the surface around the buoy that marks the wrecks’ position.

Work goes on around us in Guam’s largest port as it has done for two centuries, a tug gently nosing a vast container ship into its berth a couple of hundred meters away.

The harbor was first used by the Spanish in the 1520s (the islanders had been using it for 2,000 years before that) and went on to be developed as an important port of call on the galleon trading routes linking Manila and points across the Pacific with Acapulco and the homeland. The surrounding area is now part of the U.S. naval station. Glass Breakwater, which extends like a protecting arm to the north, is named after the captain who claimed Guam for the U.S. in 1898.

One hundred years of American influence (albeit interrupted) have turned parts of the island into lookalikes of the mainland United States, complete with sprawling malls, pick-up trucks, condos and the ubiquitous fast-food outlets. But that’s just the point for many of Guam’s visitors; the island is hugely popular with Japanese and Korean tourists, particularly young couples or those with children, and it is just a short flight from Tokyo or Seoul.

The opportunity to fire an M-16 or AK-47 in one of the roadside shooting ranges and gun shops is irresistible to many tourists, if the signs displayed in kanji or hangul characters are any indicator.

America is not quite all-pervasive. The indigenous Chamorros people are of Indonesian-Filipino descent, and rival chieftains lived in feuding disharmony until the Spanish arrived. By 1695, the Spaniards had subjugated the local population, in the process slashing their numbers from 100,000 to just 5,000 — virtually all women and children who had been spared the sword.

Today, however, the Chamorros make up the largest ethnic group on the island and are fiercely proud of their heritage. The most prominent reminders of Guam’s ancient history are the Latte stones: upright limestone posts standing up to 7 meters tall and capped with rounded stone or coral, dotted around the island. Guam’s small museum, in the capital Agana, displays shards of pottery and other archaeological discoveries.

The museum also has a section dedicated to Sergeant Shoichi Yokoi, a straggler from the Imperial Japanese Army who was discovered hiding in the rugged interior of the island in 1972, 27 years after Japan’s surrender, unaware that the conflict was over. Many of his erstwhile comrades in arms never returned to their homeland, killed trying to repel the American invasion. Even today, construction work is frequently halted when human remains or unexploded munitions are discovered.

Off the coast, however, relics of the war are less likely to have been disturbed. A landing craft rests in about 15 meters of water in Agat Bay, to the south of Apra Harbor. The bay was one of the main landing beaches for the American invasion force. Not far off to the north is a tank turret and a length of track.

The open-topped landing craft rests upright on a broad stretch of white sand, clogged with silt and with its bow door torn open. Its glass windows are intact and it does not take long to explore the vehicle in its entirety.

Surfacing, I realize the tranquil beach before me is where the Marines stormed ashore. Palm tree branches are rattling in the breeze. Peace has come back to Guam, and apparently it means to stick around.

In line with COVID-19 guidelines, the government is strongly requesting that residents and visitors exercise caution if they choose to visit bars, restaurants, music venues and other public spaces.