The beauty of spaces all over town

The best view of Commonwealth Avenue Mall is from one of its benches. (David Kamerman/Globe Staff)

COMMONWEALTH Avenue in Back Bay, long called "one of the most beautiful streets in America." It is a matter of proportion, a quality of space often difficult to define in words, but you know it when you see it. The combination of the central mall, the rows of trees, the continuity of five- and six-story buildings. Take a walk. Your sense of the space is always changing - different times of day, different seasons, a sunny day, or a cloudy day. The enclave of small downtown streets around the Grain Exchange Building. My particular favorite is Custom House Street (between Broad and India streets). A short narrow street. Dappled light under a canopy of linden trees; two cafes with tables facing the street; welcoming benches. Historic and contemporary buildings work together here - proof that, with careful design, the mix of old and new can create a welcoming pedestrian scale so important to Boston. Savin Hill, in Dorchester. A thriving neighborhood is gathered around winding streets, a local T stop, and a wonderful hilly park. Proof that the spirit of community has stayed strong in this neighborhood in our ever-changing city. A myriad of architectural styles, a mix of people, but always a palpable sense of belonging.

William Rawn is an architect.