for a city's central business district, although the word was virtually unknown in Britain and Western Europe, where expressions such as "city centre" (British English), "el centro" (Spanish), "das Zentrum" (German), etc are used. Even as late as the early part of the 20th century, English travel writers felt it necessary to explain to their readers what "downtown" meant. Although American downtowns lacked legally-defined boundaries, and were often parts of several of the wards that most cities used as their basic functional district, locating the downtown area was not difficult, as it was the place where all the street railways and elevated railways converged, and – at least in most places – where the railroad terminals were. It was the location of the great department stores and hotels, as well as that of theaters, clubs, cabarets, and dance halls, and where skyscrapers were built once that technology was perfected. It was also frequently, at first, the only part of a city that was electrified. It was also the place where street congestion was the worst, a problem for which a solution was never really found. But most of all, downtown was the place where the city did its business. Inside its small precincts, sometimes as small as several hundred acres, the majority of the trading, selling, and purchasing – retail and wholesale – in the entire area would take place. There were hubs of business in other places around the city and its environs, but the downtown area was the chief one, truly the central business district. And as more and more business was done downtown, those who had their homes there were gradually pushed out, selling their property and moving to quieter residential areas uptown. Skyscrapers The skyscraper would become the hallmark of the downtown area. Prior to the invention of the elevator – and later the high-speed elevator – buildings were limited in height to about six stories, which was a de facto limit set by the amount of stairs it was assumed that people would climb, but with the elevator, that limit was shattered, and buildings began to be constructed up to about sixteen stories. What limited them then was the thickness of the masonry needed at the base to hold the weight of the building above it. As the buildings got taller, the thickness of the masonry and the space needed for elevators did not allow