East Toward Tucson
It's a long stretch of desert from Yuma east to Tucson, and there's not much to break up the monotony of the drive. However, keep an eye out for exit 67, the Dateland exit. Although Dateland Date Gardens (tel. 928/454-2772; www.dateland.com) is little more than a gift shop and diner, it is well known for its thick and creamy date shakes (on a hot afternoon, nothing tastes better).
The next exit to watch for is exit 102 (Painted Rock Dam Rd.). Getting off at this exit will lead you north to an impressive collection of petroglyphs at the Bureau of Land Management's Painted Rock Petroglyph Site. To find this ancient rock art, drive north on Painted Rock Dam Road for 11 miles to a left turn onto dirt Rocky Point Road. Continue another 1/2 mile to the parking area. There is a $2 day-use fee here. For more information, contact the BLM Lower Sonoran Field Office, 21605 N. Seventh Ave., Phoenix (tel. 623/580-5500; www.blm.gov/az/st/en/fo/lower_sonoran_field.html).
West Toward San Diego
West of Yuma, I-8 heads out across the California desert toward San Diego, soon passing through barren, windswept sand dunes that Hollywood has long used to represent the Sahara. This region may seem like it's a long way from anywhere, but if you pull off the freeway 9 miles west of Yuma at exit 164 (Sidewinder Rd.), you'll find yourself in the "town" of Felicity (tel. 760/572-0100; www.felicityusa.com), which, according to town founder Jacques-Andres Istel, is the center of the world. Actually, it was a dragon in a fairy tale that claimed that Felicity was the center of the world, and who's going to argue with a dragon? The fact that Istel wrote the fairy tale shouldn't matter. Make a pilgrimage to this unusual attraction, and you can stand inside a pyramid at the "exact" center of the world. As an added bonus, you can admire Istel's monument to the history of French aviation and marvel at his granite remembrance walls. The Official Center of the World is open for tours from Thanksgiving to Easter.