A groundbreaking ceremony will be held at 2 p.m. today to mark the beginning of a project to rehabilitate the downtown Des Moines Younkers building at 713 Walnut St. The building is undergoing a comprehensive restoration and conversion into 120 apartments and retail and office space. Demolition is  underway, and substantial completion is expected by November of 2014. Those attending the ceremony are asked to enter at the Seventh Street skywalk through the Greater Des Moines Partnership building, 700 Locust St.