Skyscrapers exist in every major city in the word. from new york city,shanhai,kuala lumpur,beijing,chicago or dubai, you will come across many tall skyscrapers.Only a century ago, It was virtually impossible to build a structure more than five or six stories high. In 19th century stone or brick buidings, each floor put more and more weight on it from the floors above. This weight limited how hight engineers could build. Today, different building techiques and technologies are used. But why don't very tall skyscrapers collapse under their own immense weight?