One of the most beautiful temples in Colombo -- even all of Sri Lanka -- is Seema Malaka. It's a Buddhist temple situated on calm and peaceful Beira Lake, not far from Gangaramaya Temple. Seema Malaka was designed to be a place for meditation and rest, rather than worship. It's a quiet spot from which to retreat from the hustle and bustle of Colombo.
The temple you see today is a replacement for one constructed in the late 19th century which sank into the lake in the 1970s. In 1976, famed Sri Lankan architect, Geoffrey Bawa (the father of "tropical modernism" style), was hired to redesign and construct the temple. Bawa's design was said to be influenced by the ancient monasteries of Anuradhapura.
The temple is simple yet elegant and is constructed on three platforms over the lake which are connected to the mainland and with each other by pontoon bridges.
All three platforms have numerous seated Buddha statues and one houses a Bodhi Tree grown from a branch of the Jaya Sri Maha Bodhi tree in Anuradhapura (itself grown from a cutting of the tree under which the Buddha attained enlightment).
Within the largest platform is a replica of the Emerald Buddha from Bangkok, a gift to Sri Lanka from the people of Thailand.
Seema Malaka, like all Buddhist temples in Sri Lanka, is open to people of all faiths. No entrance fee is charged. And when done with the temple, cross another bridge to one of the islands in Lake Beira.