More than 1,000 people are expected to attend the National Main Streets Conference, May 22-25 at the Polk County Convention Complex in Des Moines. The city was selected last summer by the National Trust for Historic Preservation to host the event, which will focus on developing downtown areas through historic preservation as well as green strategies to help recruit, retain, strengthen, support and showcase local businesses. About 50 educational sessions are being planned. Main Street Iowa, a program of the Iowa Department of Economic Development’s Downtown Resource Center, is helping coordinate the event. For more information or to register, click here.