With a population near 21 million people in the greater metropolitan area, Mexico City is one of the largest cities in the world. And, according to projections, that population is likely to increase. The United Nations estimates that by 2050, 70 percent of the world's population will live within city limits. In Latin America, that number is expected to be closer to 90 percent. So, for cities like Mexico City, it is essential that they make the move toward a "smart city" status. While Mexico City leads the way in Latin America, urban mobility and sustainability expert Daniel Madariaga hopes to help Mexico City reach the top of the list when it comes to smart cities worldwide.