Looking southwest at the three-story Beaux Arts style Municipal Building and the Walnut Street Bridge from the Locust Street Bridge. The Des Moines City Hall building (Municipal Building) was designed by Proudfoot and Bird and built by Charles Weitz's Sons Construction Company of Des Moines in 1911. The Walnut Street Bridge is a closed-spandrel arch bridge which was built in 1911 by John Wheeler Construction Company of Geneva, Illinois. Its total length is 503.3 feet. 1913 postmark. Number 6420.