If you want to get a private submersible? The VAS submersibles from US-based Nautilus Submarines is one of the best options on the list. The VAS is the only private submarine offering the option of a Diver Lockout which allows you to exit the submarine underwater while underwater. The VAS submersibles can accommodate up to 12 passengers and the Mk III version featured above carries five passengers and can do up to 10 miles or 6 knots, which allows for an 8-hour mission time in addition to a 96-hour backup, providing over four days of underwater protection. It'll set you back $2.7 million.