Beyond the Rincon Mountains section of Saguaro National Park, 25 miles or so from downtown Tucson via the Old Spanish Trail, Colossal Cave (520/647-7275, daily, $5 per car, plus $16 and up per tour) is another great place to stop. A huge old limestone cavern that offers a cool (in every sense of the word!) escape from the sweltering summer heat, this is one of the state’s most enduring tourist attractions. (Avid cavers will appreciate comparing Colossal Cave, a “dry” cave, with the newly opened Kartchner Caverns, a “wet” cave where the humidity will have you dripping with perspiration.) Colossal Cave was used in Wild West times by train robbers who escaped here with $72,000 in gold and currency. Most of the limited “development” here (footpaths, a museum, and a gift shop) was done as a Civilian Conservation Corps project during the New Deal 1930s.
The surrounding ranch land has been opened as a nature reserve with hiking, horseback riding, and mountain-bike trails. The ranch buildings have been preserved as a museum of early Arizona life.