Burnham and Root was one of Chicago's most famous architectural companies of the nineteenth century. It was established by Daniel Hudson Burnham and John Wellborn Root. During their eighteen years of partnership, Burnham and Root designed and built residential and commercial buildings. Their success was crowned with the coordination of the World's Columbian Exposition (World's Fair) in 1893. The two men met when they worked as apprentice draftsmen in the offices of Drake, Carter, and Wight in 1872. A year later they established their own architecture office and began work by building private residences for the wealthy elite of Chicago's meat industry. Both of them married into wealthy families which allowed them to establish a basis for their business. "Daniel Hudson Burnham was one of the handsomest men I ever saw," said Paul Starrett who joined Burnham and Root in 1888 (later he designed the Empire State Building). "It was easy to see how he got commissions. His very bearing and looks were half the battle". While Burnham was the pragmatic designer and impressive salesperson, Root became the creative genius of the company. When Burnham and Root were together, one woman said "I used always to think of some big strong tree with lightning playing around it". Louis Sullivan, the famous architect, called Burnham "a colossal merchandiser" obsessed with building the biggest and costliest structures of the city. The most significant buildings designed by Burnham and Root were built in the late 1880s and early 1890s. That is when Root's designs actually paved the way for modern day skyscrapers. Until then, buildings relied on exterior masonry for support, limiting their height to 12 stories. The invention of steel support beams gave him the possibility to build higher and to add more windows. The Rand McNally Building, completed in 1890, was the first ever steel-framed skyscraper in the world. Another characteristic of his designs that revolutionized modern architecture is his invention of the urban office block floor plan as we know it. As commissions multiplied, Burnham and Root had the opportunity to experiment and refine their style to create an entirely new aesthetic that was free of historical or European influences. Such buildings as the Great Northern hotel (1892), the Argyle and the Pickwick demonstrate Root's singular style. In 1890 Chicago won the competition to host the (1892) World’s Columbian Exposition, celebrating the 400th anniversary of Christopher Columbus’ discovery of America.