In 1958, Rouse built Harundale Mall in Glen Burnie, Maryland, the first enclosed shopping center east of the Mississippi River and the first built by a real estate developer. His company used the term "mall" to describe the development, which was an alternative to the more typical strip malls usually built in the suburbs (the "mall" in "strip mall" came into usage later, after the enclosed mall had been popularized by Rouse's company). Although many now attribute the rise of the shopping mall to the decline of the American downtown core, Rouse's focus at the time was on the introduction of malls as a form of town center for the suburbs.