If you're craving some mental stimulation, make sure you check out Sri Lanka National Museum. Whether it's history, culture or traditions, you'll find lots of intriguing displays to keep you entertained here.
When you've finished at this collection of historical artifacts in Cinnamon Gardens, why not make your way to Colombo City Centre, Galle Face Green, and Galle Face Beach? They're not very far from Sri Lanka National Museum and also a hit with many tourists.