Most of the cenotes are above ground pools - some shallow some deep. The Dzitnup Cenote one was by far the coolest (visually and literally) that we saw. Picture a communal swimming pool that looks like Luray Cavens, but with deeper, and clearer water, that has been used by local residents for at least hundreds of years. You access it via a tiny well-worn stair case that takes you maybe 70 feet below ground level. The main cavern is, well, of cavernous dimensions and at an amazingly pleasant temperature. When we where there it was probably about 100 degrees F outside and maybe 80 inside the cenote.