Oak Park's housing stock reflects the decades of its rapid growth while it was part of the town of Cicero, and since 1902, when it became a village. Historic preservation has been a priority since an ordinance passed in 1972 and since revised. There are 2,400 historic sites in Oak Park, the majority of which are homes built in the Queen Anne, Prairie School and Craftsman styles of architecture. The Village of Oak Park displays these online on an interactive website. Three historic districts recognize the variety of styles often standing next door to each other. The three districts are Frank Lloyd Wright, Ridgeland-Oak Park, and Seward Gunderson, outlined on a map from the village. A fourth district is under consideration as of 2015, of 176 homes built by Thomas Henry Hulbert.