Cobá lies around several lakes, which must have made it an attractive place to live. Trails through the woods lead to several scattered large mounds, and along sacbeob to outlying architecture clusters. I remember Cobá as the site of the stelae with protective roofs. Although these are sometimes pretty eroded, they would have recorded special events located with the building behind them. In that sense, they are rather like cornerstones.
Maya sites have myriad passageways, some hidden under steps on the sides of temple-pyramids. To an unknowing audience sitting or standing in the plaza below long after darkness had fallen, priests or masked deities would have disappeared and appeared like magic from one side of the steps to the other. Somehow, until I visited these sites, I missed the existence of these hidden passages.
When we came down from the largest pyramid, we encountered a tiny snake slithering as fast as possible away from us into the jungle. We took it as a good omen for our trip, which was indeed superb.