Beira Lake is an unusual feature in a crowded city — a large man-made lake right in the centre of Colombo, originally constructed by the Dutch as part of a defensive canal system. It's now surrounded by hotels, offices, and the Gangaramaya Temple complex, and the Seema Malakaya meditation centre sits on a small island in the lake, connected to the shore by a causeway.
The Pettah Floating Market occupies the northern edge of the lake, on Bastian Mawatha: a collection of stalls, some mounted on boats, selling street food and handicrafts. It's most lively in the evenings and on weekends. Paddle boats can be rented on the lake, and the view from the water — looking back at the Gangaramaya Temple and the Cinnamon Gardens towers — is one of the better perspectives on the city.