Monday the world reached an important milestone. The global population hit seven billion people, with the birth of a 5.5 pound baby girl in the Philippines. In anticipation of topping the seven billion mark, National Geographic Magazine has been presenting a year-long editorial series on population, with articles and videos on how this affects demographics, food security, climate change, fertility trends and managing biodiversity. This is one of its videos. By the way, since Monday’s historic event, the world population has gone up by more than a half million people and is climbing by about five births a second.