Houston is the large Texas city ~50 miles (80 km) from the Gulf of Mexico. It hosts the Port of Houston, one of the busiest U.S. ports by tonnage, handling petrochemicals, containers, grain, and project cargo. The port drives a massive regional economy encompassing energy, healthcare (Texas Medical Center), aerospace (NASA Johnson Space Center), manufacturing, and trade. Houston's diversity, culture, and lack of zoning make it a unique urban powerhouse.