LIVE HISTORY The Merc is more than a place to live. It is a place of history, rooted in the city's legacy of entrepreneurship, industriousness, and the good life. Completed in 1942, the 523-foot Mercantile Tower with its stately clock and soaring spire was the home of Mercantile National Bank, founded and owned by Dallas' powerhouse banker and civic leader, Robert L. Thornton. This landmark building now reclaims its place of honor amidst Dallas' vibrant skyline.