Chac Mool, one of the most beautiful cave systems in the world, is found in southern Mexico, in the heart of the Mayan world. This is the entrance to the realms of the Mayan underworld. (Photo and caption Courtesy Anuar Patjane / National Geographic Your Shot) <br> <br> <a href="http://ngm.nationalgeographic.com/your-shot/weekly-wrapper" rel="nofollow noopener" target="_blank" data-ylk="slk:Click here" class="link ">Click here</a> for more photos from National Geographic Your Shot.