Sprawling at the heart of New Mexico, where the main east– west road and rail routes cross both the Rio Grande and the old road south to Mexico, Albuquerque is, with half a million people, the state's only major metropolis. Though many tourists head straight for Santa Fe, ignoring Albuquerque, the "Duke City" has a good deal going for it. Like Phoenix, it's grown a bit too fast for comfort, but the original Hispanic settlement is still discernible at its core, and its diverse population gives it a rare cultural vibrancy. Even if its architecture is often uninspired, the setting is magnificent, sandwiched between the Rio Grande and the dramatic, glowing Sandia Mountains. Specific highlights include the intact Spanish plaza, the neon-lit Route 66 frontage of Central Avenue, and the excellent Indian Pueblo Cultural Center, while every October Albuquerque hosts the nation's largest hot-air balloon rally.