In 2006, a group of tech visionaries came together to create Twitter. In just a few years, it transformed the way people around the globe communicated with each other. Many elements that users think of as “essentially Twitter” were co-created by its users, including hashtags. “Twitter: Breaking the Bird” goes inside the creation of a once-radical, groundbreaking tech startup. The four-part series premieres Sunday at 10p ET/PT on CNN. | CNN Original Series