Paul Allen co-founded Microsoft alongside Bill Gates. He has been estimated to have been the 46th richest person in the world, and has a knack for underwater exploration. He owns the RV Petrel, a research vessel outfitted with deep sea equipment that is more capable than ever — it is the only ship equipped to explore depths reaching 19,685 ft underwater. The RV Petrel has discovered the USS Indianapolis, the USS Ward, the USS Lexington and several other wrecks from the Battle of Ormoc Bay and the Battle of Surigao Strait, as well as several other shipwrecks around the world.

On St. Patrick’s day, it made its latest discovery: the USS Juneau. The ship had been sunk in WWII, and it lay 2.6 miles under the surface of the water near the Solomon Islands. They were able to identify the Navy vessel using underwater cameras, and you can see the discovery here:

The USS Juneau was sunk on Nov. 13, 1942 at the battle of Guadalcanal. On the ship served five brothers — George, Frank, Joe, Matt and Al Sullivan all enlisted in the Navy together after Pearl Harbor (two of them had previous served), and all were assigned to the same light cruiser. They ranged in age from 20 to 27, and hailed from Waterloo, Iowa.

During the battle of Guadalcanal, the USS Juneau was eventually struck by a Japanese torpedo and was forced to withdrawal. They were hit again, and this time the torpedo crashed into a weak point, striking the ammunition magazine and causing a massive explosion. Many were killed instantly, and the only survivors were the ones outside on deck.

Of the Sullivan brothers, Frank, Joe and Matt were killed in the initial explosion. Due to logistical errors and operational requirements of overhead aircraft, a search and rescue team had not been sent for the approximate 100 survivors and most of them drowned, including Al, the youngest. The eldest, George Sullivan, would die four or five days later. Some said he succumbed to the elements, others that he was “driven insane with grief” as he was the only brother to have survived, and that he intentionally fell off the side of his raft and perished in the water.

It wasn’t until Jan. 12 that their deaths were finally confirmed and their parents were told that all of their sons had died in the war. It was because of their deaths and the deaths of the four Borgstrom brothers that the military adopted the “Sole Survivor Policy,” aimed at protecting gold star family members from the draft or combat duty. While this act is voluntary, it offers surviving family members of fallen soldiers to leave the front lines if they so choose, for the sakes of their families.

This Oct. 25, 1941 photo provided by the U.S. National Archives, shows the USS Juneau afloat just after being launched at the Federal Shipbuilding Company yard,in Kearny, N.J. | U.S. National Archives via AP

Learn more about the Sullivan brothers and their legacy here: