The cenotes are fascinating. Fresh water so close to the ocean. I'd love to know the geology that explains them. Underground limestone cave-river systems, perhaps? The Mayans had a bunch of religious practices based upon underwater caves (involving human sacrifices as I recall ... so watch your back). :-)
Quill
Thank you @quillfire, and I'm so sorry for the late reply! Not sure how I missed a handful of them here, but I feel 'icky' about it nonetheless!
As far as their geology, it's something I've read about, but at the moment, I'm pulling blanks haha I do remember the stories of the Mayans and their human sacrifices ... I trek through the jungle with rear-view mirrors on my helmet :)