Definitely swing by the ruins of Edzná on your way out of Campeche. They're about 30 miles southeast. You drive east out of Campeche on Highway 180, turn right at Highway 188, and just follow the signs to Edzná.These ruins represent the southernmost of the Classical Mayan Puuc architecture (reflecting the period from 700-900 AD), but in even earlier times (beginning in 250 BC) Edzná was famous for its agricultural production, having the most extensive canal and irrigation system on the Peninsula. Its integrated system of aqueducts and reservoirs covered several square miles across the valley floor. This was the Bread Basket of the Yucatan. Goodness but it's hot and dry now.
You enter Edzná and cross a sacbe to approach the main plaza. Looming up to your immediate left is the large main platform supporting the site's largest and grandest structure: The Building of the Five Stories, a combination temple, palace and pyramid. That's it, the tallest building in the distance on the photo's left. It's a schlep from the plaza where GB's standing up to the platform (those stairs are steeper and there are more of them than it looks), but while you catch your breath up there you will see several smaller pyramids and other structures cluster around the Five Stories.