Far beneath the waves off the coast of the Bahamas lies the Black Hole of Andros and it does not sound like a lot of fun.
Paul Rose says: "There's a layer of bacterial matter 18m down, it's incredibly oily and, as you enter, you lose all visibility.
It's unusual to smell anything underwater but, because your skin absorbs it, you can smell it – like rotten eggs. It's also baking hot, about 35º C, and you get quite disorientated."
Paul is a former vice president of the Royal Geographical Society, the base commander of the British Antarctic Survey base and is now the presenter of Oceans, an eight-parts series that covers maritime archaeology, biology, conservation, history and culture.
A breezy east Londoner, who began diving in 1969, Paul ventured into the black hole in search of evidence about how the oceans work. Located in the part of the Atlantic Ocean from which the Gulf Stream springs, it offers an insight into a past world – a snapshot of what the oceans were like three-and-a-half billion years ago.
"I've really wanted to present a series about great diving expeditions with great settings," he says.
"I've always been inspired by slightly-old fashioned films, along the lines of the programmes that first inspired me to dive, like the great Jacques Cousteau expeditions and the adventure series Sea Hunt."