People live in all kinds of places, from bustling cities to remote mountains, and from the cold tundra to hot deserts. Our physical environment can affect the food we eat, the clothes we wear, the houses we build, and how we get around. This fascinating series takes readers on a journey around the world. By focusing on familiar, everyday activities, it shows how people's lives can be very different, but also very similar, to our own. More than half the people in the world in a city. Cities are always busy! They are usually home to lots of people. Some cities have existed for thousands of years. Others are newer and still growing. Find out what it's like to live in city, from living in a skyscraper to traveling on underground trains!