D1. Koester House (1859)

421 South Seguin Avenue

Built by the city’s first physician, Dr. Theodore Koester, this is one of the city’s most impressive historic homes, with three stories, 15 rooms, and 18-inch limestone walls. This mid-19th century house, constructed in the new Anglo-American vernacular, also included a kitchen, basement, dumbwaiter, and other architectural innovations for the time period. Now an office building.