Four bridges span the Mississippi River leading into downtown St. Paul. The oldest is the Robert Street Bridge. Constructed in 1926, the 1,534 concrete span is unusually complex. It features three types of arches: barrel, rib and rainbow. It was designed to accommodate car, foot, railroad and ship traffic. The street and bridge were named after Louis Roberts, a French-Canadian fur trader. He was also an early riverboat captain in St. Paul during the 1850s. Relative to the position of the current bridge, his home was on the cliff at the bridge terminus and his Lower Landing trading post was located on the lower right.