A sacred place of worship, Pettah Hindu Temples will give you a better understanding of the area's culture. Take a few moments to learn about the significance of this site to the local people.
You're spoiled for sightseeing choice when staying in Cinnamon Gardens. Pettah Hindu Temples is a good place to start here, but there are lots of other worthwhile sights to check out. Colombo City Centre, Galle Face Green, and Galle Face Beach are near the place of worship and and will cap off your day nicely.