Circular adobe structures huddle together like muddy bubble-wrap in the ruins of Tulor, the oldest excavated village in the region. It’s an interesting diversion 11km southwest of San Pedro. You can get there by your own vehicle, driving along sandy tracks, or by riding a mountain bike. However, you’ll get more out of the experience if you go on a good guided tour.
If you go alone, there's often a Spanish-speaking guide on hand who can fill in some of the historical details (included with admission).