I went to Chaak Tun as part of an excursion with the Snorkel Shop Northern Surf and Turf Tour and was so amazed by the natural beauty of it. The water was so refreshing and the vampire bats were a bit freaky at first but then you get so immersed in the cenote, you forget they are there. Memo, our guide thru the Snorkel Shop (which I highly recommend as a tour company) made sure we were safe with helmets, life jackets and torches and pointed out amazing details to us. Catfish swim all along the bottom and the visibility was so clear. The bottom of the cenote looks so soft but it is many feet down and untouchable by me. Great timing for our visit because as we entered the cenote it was full of people but as we came out, everyone was gone and we got to jump and play in the water all alone. I would of reviewed this cenote thru the Snorkel Shop but I am new to Trip Advisor and thought I could review each tour separately as well as the company, but it turns out only one review per person, regardless of how many tours or times you visited. My apologizes to Graham and I hope you see this link!