Chinese New Year (also known as Lunar New Year), which starts on the new moon that falls between 21 January and 20 February, is celebrated by some 1.5 billion people around the world. And, as travel has become more affordable to China’s rapidly growing middle class, the holiday now accounts for an estimated 3 billion trips (called chunyun in Chinese), making the celebration the world’s largest annual human migration. The New York-based filmmaker Jonathan Bregel uses scenes of this extraordinary human flow to convey both the sheer magnitude of the movement of people and the moments of celebration that are a crucial aspect of the holiday.