When the United Kingdom announced their goal of adding 3 million new homes by 2020 to relieve pressure on an overburdened housing market, some residents probably had visions of great natural places like the London Greenbelt or Scottish Highlands filling up with new housing developments. In a country where space is at a premium, a new report by the Prince’s Foundation for the Built Environment makes the case that it’s a more economical and environmentally sounddecision to add these 3 million homes by creating “walkable, mixed use, mixed income developments instead of car-dependent housing estates.”