This chapter is concerned with all aspects of transforming the environment – what in the professional world would be called planning, landscape architecture, environmental design, urban design, and architecture. Design is an inappropriate word to use for much of the world because it implies a degree of professional specialization that does not apply to them; they build their own houses and community centres and public spaces without the help of anyone trained as a designer, architect, or landscape architect and often without the involvement of an official environmental planner. The terms are used here to refer to the process anyone goes through, trained or otherwise, in creating or transforming the environment. To that extent, children are planners and designers too when they engage in construction play. The large number of examples from the United Kingdom in this chapter is a reflection of the extent to which this country has pioneered this particular kind of environmental engagement by children.