As the pressure on land and natural resources increases due to the increasing demands of a growing population then technology of all kinds will be forced to occupy the interstices of modern urban dwellings. Just as a jar full of rocks can accommodate additional sand and the jar full of sand can accommodate additional water so the performance of vital functions will begin to occur in very small places all around us. Such is the nature of synthetic biology. Powered by sunlight the urban system will become our residence, our factory and our farm. As Feynman said: “there’s plenty of room at the bottom”.