Who knew high school science classes could be fun - and even memorable enough for a Guinness World Record. But over a thousand students in Chennai managed exactly that when they got together for a one-of-kind biology lesson on Saturday as part of the ongoing India International Science Festival. The class began with all the 1,049 students being individually tagged. Then, a local school teacher gave them a biology lesson and a demonstration on how to extract the DNA from a ripe papaya fruit.