The world's only privately owned manned submersible has a unique design and some surprising features.
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What's it like inside?
The sub itself is extremely narrow, measuring just 670 cm x 280 cm x 250 cm (22ft x 9.2ft x 8.3ft), and can carry a crew of just five people - a pilot and four passengers.
While it is bigger than competitors, passengers are required to sit on the floor with limited room to move around.
At the front of the vessel is a large domed porthole offering a viewing point, which the company claims is the "largest viewport of any deep-sea manned submersible".
The walls of the sub are also heated as conditions can become extremely cold at such depths. Wall mounted lamps are the only source of light on board.
Unusually though, it includes a private toilet for customers at the front of the sub. A small curtain is pulled across when it is in use and the pilot turns up some onboard music.
However, the company's website does recommend "you restrict your diet before and during the dive to reduce the likelihood that you will need to use the facilities".
