Swimming with dolphins is a bucket list staple, and this trip lets you tick off the once-in-a-lifetime experience in style. Your venue for the day is Cancun's Xel-Ha :the largest natural aquarium in the world. The dolphins here live in an environment almost identical to their natural habitat, so swimming with them is a really similar experience to joining them in the wild. You'll have plenty of time to play with the marine mammals, who challenge canines for the title of ‘man's best friend'. You can give them a hug, lean in for a kiss, and watch in awe as they jump out of the water in a flurry of twists and turns.