Watching Lanka is one of the best activities in the world to see one of the only recorded resident blue whale colonies in their natural habitat. It will be a once-in-lifetime experience for sure. In warm Indian ocean you can see Blue whales, Bryde is whales, Sperm whales, Fin whales, sometimes Killer whales, and Common dolphins, Bottlenose dolphins, Spinner dolphins, Risso is dolphins and Striped dolphins.
Slither your way towards the southern province of Sri Lanka to Matara, that is 2 and a half hours away from Colombo. Here, in a little hamlet called Telijjawila you will find the snake farm.