Starting from Gansbaai I attended a cage diving tour to see the great white shark. Cage diving is actually a pretty safe way to encounter this predator.
The only annoying thing at that time was the water temperature. Usually around 15 degrees it can be quite cold even in a 7mm wetsuit. Therefore the cage was lowered down underwater for max 10 minutes. Another point was the visibility underwater which was not so good and it was just a matter of luck to see the shark approaching. I had only a visibility of around 3 meters, which was too short for good pictures. Anyway, one can take the chance to shoot pictures on board from the upper deck (if there is one).

To attract the shark the boat crew casted a chum slick made of crushed tuna/skipjack or sardines. The Great White sharks can smell this chum slick from a considerable distance. In addition, the crew pulled decoys or bait lines closer to the cage and boat to lure the magnificent creatures even closer.
The white shark is usually between 4 and 5 meters long and can weigh up to 3.5 tons. I have seen pictures of white sharks jumping out of the water to catch the prey - hard to believe that a 3 ton fish can jump that high. The great white shark has no natural predators other than the Orca. It is arguably the world's largest known extant macro predatory fish.

It is believed that the true lifespan of great white sharks is 70 years or more.
A great white displays countershading, by having a white underside (that is why it is called white shark) and a grey dorsal area (sometimes in a brown shade as you can see on my pictures) that gives an overall mottled appearance.