Apparent in this photograph is the coalescing of the corridor between Houston, the country’s fourth largest city, and Galveston Island, 45 miles (72 kilometers) southeast of downtown Houston, resulting in shrinking availability of rural, agricultural lands. The Texas City Dike [5 miles (8 kilometers) long], originally constructed as a protective breakwater for the Texas City Ship Channel and port, juts southeastward toward the mouth of Galveston Bay, whose entrance is visible between the eastern end of Galveston Island and the western tip of Bolivar Peninsula. Discernible are highly reflective concentrations of oil refineries and petrochemical plants in Texas City and along the Houston Ship Channel; Interstate Highway 45, the major artery that connects Houston and Galveston Island; and other highway systems.