Honmachi flourished as a center below Osaka Castle, and even to this day it is known as one of Osaka's representative business districts. When Toyotomi Hideyoshi unified the nation, Honmachi was the economic center, bringing specialty products from various regions into a single market as the "Kitchen of the Nation." During the construction of Osaka Castle, a large number of retainers and warriors gathered here to aid in its building, consequently resulting in the beginnings of the town. In 1970, the world's fair was held in Osaka, and to coincide with it, the Senba Center Building was opened. It is an iconic building in Honmachi, containing stores, restaurants, and offices. Furthermore, Honmachi Bridge, which runs through the lower part of the Hanshin Expressway No.1 Loop Route, was installed during the castle's construction, and is known as the city's oldest bridge. And on its northern end is Nishimachi Bugyosho, which used to function as the administrative center of Osaka. The existing bridge is a replacement from 1923, and is supported by stone piers that make it a sturdy construction.