Monumental in size and personality, the Great Dane towers over other larger breeds. Often thought to be the world’s tallest dog, only the Irish Wolfhound can claim to be taller. Gibson the Great Dane, however, currently holds the Guiness world record for tallest dog. Great Danes are gentle giants, friendly and calm, despite their intimidating size. They do require love, attention, and plenty of space to exercise those long limbs, though and tend to have a shorter life span.