"Historic houses are very soulful places," notes Kim Prothro Williams, an architectural historian with the D.C. Historic Preservation Office. She says mid-century style homes, those built in the mid '50s to early '60s, are a dying breed in the area. "We have noticed that there have been threatened resources," Prothro Williams said. "Many mid-century houses are being demolished." She's conducting a survey to account for this type of architecture: homes with clean lines, flat roofs and asymmetrical profiles. So far, 200 dwellings with some form mid-century style or attitude have been accounted for. "Before it's too late, we want to at least collect information on those surviving houses," Prothro Williams said.