Diving the Blue Hole has been famous since Jaques Cousteau visited the site in the early 70`s. The hole is different in that you will see stalactites coming from the roof of an overhang at 130 ft. The bull sharks circling above us on our ascent made the dive for me though.
Cost is around USD 150 for 3 tanks.
The Cays are a must see if you can afford to spend a night or two.
Brodies off of Albert Street - It has everything and then some that you can imagine.
Water Taxi - That's always a great things to do even if its for the day.
Exploration with a guide explaining Mayan history
Small Mayan ruin site partially excavated. Mountain like hills covered in jungle and trees still cover other ruins.