But the few places where it is still possible to see such wildlife spectacles are increasingly under threat from the burgeoning commercial shark industry, according to the environmental pressure group WildAid.
Large schools of the bizarre-looking hammerhead shark are part of the magical allure of world heritage marine parks such as the Galapagos Islands and Cocos Island off Costa Rica.
But the few places where it is still possible to see such wildlife spectacles are increasingly under threat from the burgeoning commercial shark industry, according to the environmental pressure group WildAid.
It claims the wasteful practice of finning, where the shark's fins are sliced off and the carcass discarded, is putting populations of the ocean's top predator under mounting pressure, even in danger of collapse.
Worse still, WildAid claims, the demand for shark fins as an expensive delicacy has led to the growth of illegal fishing in precious marine reserves like Galapagos and Cocos.
Elephant slaughter
Eliecer Cruz, director of the Galapagos National Park Service, said: "The illegal fishing for shark fins in the Galapagos has increased dramatically in the past few years.
According to WildAid, about 100 million sharks are killed every year in a trade which it likens to the scandal of the slaughter of elephants for their ivory.
The fins themselves are dried and often end up in soup in Chinese restaurants all over the world, commanding prices of up to $80 per pound.
Management plans
A single bowl of soup can fetch as much as $150. There is no scientific evidence whatsoever to back up claims that the fins possess any beneficial medicinal qualities for man though in the Far East, sharkfin soup is as much as about prestige as anything.
Sharks have had a bad press for decades, and there are those who believe the "only good shark is a dead shark". But they are a vital part of the food chain, keeping the world's oceans in check.
Some species have limited protection in certain parts of the world, but if the decline in shark populations is to be reversed, say the experts, governments will need to draw up management plans.
It is an issue which is to be discussed at the United Nations Food and Agriculture Organisation meeting in Rome between 26 and 28 February.
Tourist trade
Peter Knights, director of WildAid, said in the group's latest report, The End of the Line, that human activity posed a global threat to sharks.
"Solutions will come only from learning more about sharks, reducing fishing pressure, stopping unnecessary catches, monitoring shark fishing and trade, and more effective enforcement of regulations," he said.
An irony today is that a live shark in the wild can be worth thousands of dollars to the booming tourist trade in diving.
Gradually, people are realising that to share a close encounter with these remarkable animals is difficult to put a price on.