Not only are people more likely to walk around in cityscapes with open and lively façades, but the kinds of things that they do in such places actually change. They pause, look around and absorb their surroundings while in a pleasant state of positive affect and with a lively, attentive nervous system. Because of these kinds of influences, they actually want to be there. And because of such effects, many cities have carefully designed building codes for new construction that dictate some of the contributing factors to happy and lively façades: in cities such as Stockholm, Melbourne and Amsterdam, building codes specify that new construction cannot simply be parachuted into place. There is a hard lower limit on the number of doorways per unit of sidewalk length, and there are specifications for transparency between the building and street in the form of clear windows with two-way views.