Fourth — Octopus, $200 million — With an impressive 416 feet, this boat is quite the bully of the seas. Armed with lavish and luxurious amenities such as seven smaller boats, two helicopters, a 10-person submarine and a robotic submersible, this yacht is more than impressive. Currently owned by Paul Allen the co-founder of Microsoft, this yacht is the ninth largest in the world and Mr. Allens second superyacht.