Спереводом,)the structural definition of the word skyscraper was refined later by architectural historians, based on engineering developments of the 1880s that had enabled construction of tall multi-story buildings. this definition was based on the steel skeleton—as opposed to constructions of load-bearing masonry, which passed their practical limit in 1891 with chicago's monadnock building. philadelphia's city hall, completed in 1901, still holds claim as the world's tallest load-bearing masonry structure at 167 m (548 ft). the steel frame developed in stages of increasing self-sufficiency, with several buildings in chicago and new york advancing the technology that allowed the steel frame to carry a building on its own. today, however, many of the tallest skyscrapers are built almost entirely with reinforced concrete. pumps and storage tanks maintain water pressure at the top of skyscrapers.
