Gansbaai is considered as the Mecca of Great White Shark diving. Why? Because 6 km (4.5 miles) from the shore is 'Shark Alley' : a 600M/2,000ft long and 30M/100ft wide shallow channel lying between Dyer Island, a natural marine birds sanctuary, and Geyser Rock, home to 15,000 to 50,000 Cape Fur Seals depending on the seasons. For White Sharks, Geyser Rock is some kind of a McDonalds, and Dyer Island's area is undoubtly the number one spot in the world in terms of concentration of Great White Sharks : during the best season (April to October), one can easily see up to 10 different sharks over one single daily trip (unofficial record : 26 !). It has to be noticed that, even if they have a different behaviour during summer and thus are sometimes more difficult to watch, sharks are there all year long. The area is suspected to be some kind of a breeding ground, and seeing very young individuals (1,5M/5ft) is not more uncommon than huge 5.5M/18ft pregnant females. But a mere 3M/10ft sub-adult White Shark is a very big and impressive animal, especially watched underwater from the security provided by an aluminium cage.