#SeeingRedSeries Cat walk connecting the two parts of the Wrigley building complex, the old HQ of Wrigley & Co. built in 1920’s. This was Chicago’s first air-conditioned office building and what is so interesting is that the facade is not typical stone, but rather it is terra-cotta with white glazing, The building literally glows during the day. Standing right on the river bank, off Michigan Ave, this is a must spot for sight seeing for visitors.