 The Old St. Louis County Courthouse (locally known as the "Old Courthouse") was completed in 1864 and was notable for having an early cast iron dome and for being the tallest structure in Missouri until 1894.Finally, a customs house was constructed in the Greek Revival style in 1852, but was demolished and replaced in 1873 by the U.S. Customhouse and Post Office.Because much of the city's early commercial and industrial development was centered along the riverfront, many pre-Civil War buildings were demolished during construction of the Gateway Arch.