Houston, United States

Houston — 'Space City' — is the largest city in Texas and the fourth-largest in the United States, a low-slung, fast-growing metropolis built on energy, medicine and space exploration. Its single most famous claim is cosmic: NASA's Johnson Space Center is mission control for human spaceflight, and 'Houston' was the first word spoken from the surface of the Moon ('Houston, Tranquility Base here, the Eagle has landed'). The adjacent Space Center Houston, the official visitor centre, holds the largest collection of Moon rocks on public display and is the city's top draw. Houston is also one of the most ethnically diverse cities in America — repeatedly ranked the most diverse large US city — and that mix shows up most deliciously at the table, from Viet-Cajun crawfish to taquerias, Gulf seafood and serious barbecue. Culturally, the walkable Museum District packs 19 museums into four zones, led by the vast Museum of Fine Arts and the free, Renzo Piano-designed Menil Collection in leafy Montrose, while the Theater District downtown is one of the few US cities with resident companies in every major performing-art form. Green relief comes from Buffalo Bayou Park and Discovery Green, and the Texas Medical Center — the largest medical complex on Earth — anchors the city's south side. Each spring the Houston Livestock Show and Rodeo, the world's largest, fills NRG Park. METRORail's light rail links downtown, the Museum District, the Medical Center and NRG Park, though greater Houston remains car country. George Bush Intercontinental (IAH) is the main international gateway, with William P. Hobby (HOU) closer in. The climate is subtropical — hot, humid summers and mild winters; spring and autumn are the most comfortable times to visit.