The United Kingdom's HMS Victory set sail in 1737. At the time, it was the most advanced warship in the world. It carried 100 of the most powerful guns ever made. It was a formidable vessel. And it sank in 1744. Its disappearance was a huge loss to the Royal Navy. It was also a total mystery. People long believed it had run aground on a small island. It wouldn't be found for more than 260 years. It turned out centuries of assumptions were completely wrong. In 2008, a shipwreck exploration company found the HMS Victory. And it was found where no one had thought to look.