smalltown sheriff, with the unforgettable whistle, from mayberry to matlock. our tribute to andy griffith. we have fireworks. and it s our biggest blowout fourth ever. gma s party in the usa. and a good morning, everyone. and happy birthday to you, america. 236 years old. you don t look a day over 150, i have to tell you. george, robin, both off today. some argue that sam s only half here. we have amy robach with us. and that crowd has already won the spirit award. they are here, despite those shots, expected to be a very hot one out there. more than 40 million americans hitting the road today. gas is cheaper. we have the latest before you head out the door. we ve had that moment of brain freeze when we eat ice cream. what s really going on in our brain? we actually have the science behind it. who knew that doctors and scientists were studying this malady. they have answers for you. we are expected to begin the hottest fourth of july ever. how hot is it? take a