We headed out early this morning for our visit to Chichen Itza. On the way we went to visit one of the Cenote's (sinkholes) that are common here in the Yucatan. I learned that there are no rivers in the Yucatan due to its interesting geology. The Yucatan sits on top of limestone. When it rains all of the water filters down through the porous limestone. Over time part of the limestone will crumble and open up a sinkhole full of fresh water.