Alameda is probably best known for its residential Victorian architecture. "There are about 3,000 Victorian-era homes in Alameda, one for every 25 people who live here. In addition, there are another 1,000 historic buildings, including City Hall and many of the shops along the Park Street and Webster Street commercial corridors." [source]
This article provides an excellent history that explains why there are so many Victorians in Alameda. Long story short, they more mostly built in the late 1800s/early 1900s when Alameda got railroad service and was considered an SF suburb (mostly for wealthy people). By the 50s and 60s, many of the Victorians were considered dumpy and old-fashioned, and were torn down and replaced with apartments. "In the 1970s, the Alameda Architectural Preservation Society, then called the Alameda Victorian Preservation Society, formed to protect the old houses. The group helped pass a local initiative, Measure A, which prohibits the construction of buildings with more than two housing units." [source]