Perhaps no natural feature defines southern Arizona, and Tucson in particular, more famously than the towering, forklike, slow-growing saguaro cactus, for which Saguaro National Park (520-733-5153) is named. This 91,500-acre park is divided into two section, which bracket the city of Tucson on the east and west (they're about 30 miles, or a one-hour drive, apart from one another). Scenic loop roads and many miles of hiking trails wind through each section, although most of Saguaro National Park is designated wilderness.

There's also a paved bike trail in the eastern section, and a gravel bike path in the western one. Each of the two park districts also contains a visitor center, with information about not only these curious-looking, captivating plants but also the hundreds of other flora that thrive in this harsh yet stunningly beautiful desert environment.

If your curious about saguaro cacti, which grows unbelievably slowly and doesn't produce any branches until it's at least 50 years old, check out the exhibits in the visitor centers as well as the park's online Saguaro Cactus Question & Answer Guide. Also useful is the official park map, which shows detailed overviews of both the eastern Rincon Mountain District and western Tucson Mountain District of this popular park. Both sections offer plenty to see and do, and because they're rather far apart, it's best to allow at least a full day to explore each section.

If you have only a couple of hours, pick the section nearest to where you're spending time in Tucson and plan to stop by the visitor center, drive part or all of the loop drive, and perhaps stop for a short hike.

Both sections are similarly interesting and beautiful - the western Tuscon Mountain District is perhaps best regarded for its dramatic sunsets, while the eastern Rincon Mountain District offers the best light in the morning.