Prince William and Kate Middleton's royal baby boy has arrived. The newborn is third in line to the British throne, after grandfather Prince Charles and father Prince William, and follows in the footsteps of his or her great-grandma, Queen Elizabeth II. Eighty-seven years separate the newest member of the royal family from the reigning monarch, who has been on the throne for 61 years. (Oh, how time flies!) Much has changed since Elizabeth's birth in 1926 when U.S. postage stamps costs 2 cents, Calvin Coolidge was the U.S. president, and classic children's book "Winnie-the-Pooh" was published. Here's a look back at some of the pop culture milestones from Elizabeth's birth to Prince Wiliam's to today.