Snorkel with whale sharks off Mexico’s Yucatán Peninsula
Whale sharks--the world's largest fish--offer guaranteed sightings in only a few places on earth; and one is off the Yucatan Peninsula in Mexico. From June through September numbers of these massive beasts head to Mexico's northeastern tip to feed and mate, offering opportunities for whale watching and even swimming with the whales.
According to Lonely Planet, the best place to stay is Isla Holbox in Mexico’s Yum Balam Biosphere nature preserve. And one can swim with the whales for about $80 per person.