In 1885 architect William Le Baron Jenney used steel framing to construct the Home Insurance Building in Chicago. At ten stories, it was the tallest office building in the world. People looking up at the building from the sidewalk called it a skyscraper. Within a decade, Chicago would have three more skyscrapers: the Tacoma Building (1889), the Masonic Temple (1892), and the Reliance Building (1895). By the early twentieth century, Chicago was becoming famous for its buildings. Some of the most famous architects in the world were working in the city. The styles and new construction methods these architects used became known as the Chicago School. Louis Sullivan (1856–1924) was a leader of the Chicago School. He worked on an architectural style known as modernism. Modernism began with new construction technology such as steel framing. A building’s outside walls no longer needed columns, arches, and other supporting pieces. New buildings could have much simpler shapes and decoration. The new shapes would emphasize the vertical (the up and down direction).