The late Geoffrey Bawa was Sri Lanka’s preeminent 20th-century architect; he pioneered a tropical Modernist style and was a huge influence on contemporary Asian architecture. Bawa bought the first of a row of four houses set in a genteel neighborhood cul-de-sac in 1960, and remodeled it. Over the ensuing decade he acquired the other three buildings to create this airy, light-filled residence, Number 11. You can tour the residence by appointment only.