On October 31, 1780, the HMS Ontario, a 22-gun brig sloop was swamped by a gale as she crossed Lake Ontario from Fort Niagara. Lost with all hands, 60 British soldiers, 40 mainly Canadian crew and possibly as many as 30 American prisoners-of-war, she remained at the bottom of the lake for 228 years, before being discovered some 500 feet down, covered in mussels. She is in such good condition, perfectly preserved by the freezing temperatures, that two of her window panes are still intact, and her masts are still standing. Interestingly, the ship is being treated as a war grave, and no plans are being made to raise it or to recover any of its artefacts. It is the only fully-intact British warship to be discovered in the Great Lakes, and is considered to be the Holy Grail of the nearly 4700 Great Lakes shipwrecks.