The urbanization in the second half of the 19th century induced other significant changes that would ultimately change the kitchen. Out of sheer necessity, cities began planning and building water distribution pipes into homes, and built sewers to deal with the waste water. Gas pipes were laid; gas was used first for lighting purposes, but once the network had grown sufficiently, it also became available for heating and cooking on gas stoves. At the turn of the 20th century, electricity had been mastered well enough to become a commercially viable alternative to gas and slowly started replacing the latter. But like the gas stove, the electric stove had a slow start. The first electrical stove had been presented in 1893 at the World's Columbian Exposition in Chicago, but it was not until the 1930s that the technology was stable enough and began to take off.