Aston Martin's ultimate toy for your superyacht - a submarine

IT'S the only time you'll want to put your Aston Martin under water. The British automaker unveiled its first submersible design on Thursday at the Monaco Yacht Show.

Dubbed Project Neptune, it's a three-person vehicle with silver, blade-like pontoons and an acrylic bubble of a cabin for maximising underwater views.

Aston Martin expects the sub will be available in about a year and will be priced around at US$4 million, the company's chief creative officer Marek Reichman told Bloomberg. For comparison, a V8-powered DB11 will run you nearly US$200,000.