High Quality Content by WIKIPEDIA articles! The Mercantile National Bank Building (known colloquially as The Merc) is the former home of the Mercantile National Bank, later MCorp Bank, located at 1700 Main Street in downtown Dallas, Texas (USA). It is a contributing structure in the Main Street District. The design of the skyscraper features Moderne styling from the Art Deco era and was designed by Walter W. Ahlschlager. The building has a series of setbacks that is crowned by an ornamental four-sided clock along with a decorative weather spire. The Merc was the main element of a four-building complex that eventually spanned a full city block.