There are lots of stray pyramids around Mexico City. Some have more to see than others, but Mexico has been working to restore many and they're interesting to see. We were able to stop by Acatitlan (St. Cecilia). There's a church, as there often is, right next to the site, along with a museum. Most of the ruins have been built over or destroyed, but the area around the pyramid is a lovely spot and you can climb the pyramid.
It was a little tricky to get to it. There were no signs (there were some for Tenayuca which is nearby) and it's tucked away, but we did make it there. We also ate lunch nearby. We'd mostly been eating street food or in restaurants, but this was a home restaurant where we each had a $3 meal that included a plate of red rice, a bowl of vegetable soup, and a main dish with plenty of meat. Another reason to love Mexico. And for a few more pesos, we each had a bowl of strawberries with crema which is way better than strawberries with cream.