The arrival of the 20th century brought a convergence of economic factors that fueled rapid growth in Houston, including a burgeoning port and railroad industry, the decline of Galveston as Texas's primary port following a devastating 1900 hurricane, the subsequent construction of the Houston Ship Channel, and the Texas oil boom. In the mid-20th century, Houston's economy diversified, as it became home to the Texas Medical Center—the world's largest concentration of healthcare and research institutions—and NASA's Johnson Space Center, home to the Mission Control Center.