Kalani Raja Maha Viharaya.

Located about 9 km away from Colombo, the Kelaniya Raja Maha Viharaya is one of the most significant Buddhist temples in Sri Lanka. The temple had been built more than 2,000 years ago and contains images of reclining and preaching Buddha along with frescoes depicting incidents from his life.

Website

kelaniyatemple.org (opens in a new tab)