With Simon Cowell's triumphant comeback, AGT season 16 kicks off with performances by The Canine Stars, dog lovers who put on a lovely imitation dog show; 10-year-old Peter Rosalita who's got an amazing voice; Aidan Bryant whose self-taught aerial act gets his mom in tears; Mr. Cherry breaking the world record with his strong butt; and Northwell Nurse Choir of only part time singers, and yet are given the Golden Buzzer. Find out who's giving it!