How did new construction techniques change city living space?

New construction techniques allowed the building of high-rise buildings and sky scrapers - which made extremely dense population possible. New construction techniques also allowed for mass transit systems to move large numbers of people into and out of cities, sinking building basements below the water table in cities near the oceans, distributing massive amounts of power to run cities, and infrastructure to bring in huge amounts of water and take out massive amounts of waste (in sewers) to allow congested cities to function.