For a phenomenon of another sort, take a whale-watching cruise with the non-profit Pacific Whale Foundation at Ma'alaea Harbor.  It seems even humpback whales know a good thing when they see it, and the waters around Maui serve as the whales' winter birthing grounds.  Humpback whales… are widely known for slapping their flippers, breaching, and for the haunting song-like melodies the males communicate with.  Seeing the large whales interact in their natural environment is a humbling experience that will stay with you for a lifetime.