One of the things that helps make Washington's vistas so grand--but continually frustrates developers and architects--is the district's Congressionally-imposed115-year-long ban on skyscrapers. Congress passed the 1899 Height of Buildings Act, and then modified the law in 1910, creating a complex set of restrictions based on location and street width.
It might seem intuitive that the skyscraper ban was imposed to protect views of the U.S. Capitol and the Washington Monument. But oddly, Congress was prompted to restrict construction heights because of Dupont Circle residents' griping about being overshadowed by what today is regarded as one of the District's architectural treasures--The Cairo apartments at 1615 Q Street NW.