I'll never forget my first time diving with sharks. I'd made my way to

Simon's town in South Africa. The plan was to get as close as possible to a great white shark.

These animals can reach up to 7 meters in length. That's huge about the same length as a caravan

and getting into the water with them would be the perfect way of getting a real sense of their sheer bulk and how their stealth and speed

make them such formidable predators.

Now some people are bold enough to dive with Great Whites in the open ocean, but I wasn't quite willing to take any chances.

Well, not yet anyway.

So I opted for the more traditional cage diving approach.

With all our checks complete I entered the cage.

As the cage plunged beneath the surface of the water, the shock of the icy South Atlantic

ocean sent my heart rate through the roof.

I took a few moments to take some deep calming breaths. I was now completely out of my comfort zone and in the realm of the biggest predatory fish in the world.

The water visibility was so poor.

I could barely see two or three meters beyond the cage. All I could do was wake anxiously in the murky blue.

All of a sudden a voice radioed through to my headset.

Okay, get ready, Patrick, the sharks coming in. What's it feel like to be that close?

But I stayed silent. I still couldn't see anything.

Then it hit me, quite literally, because although I couldn't see the shark, I could feel something banging against the cage.

I turned around and there it was, our great white shark thraking against the metal bars.

There was no mistaking its power.

With every flick of its tail the cage was thrown against the boat again and again.

After what seemed strangely like both an eternity and a split second,

...