Next on the docket: Louis Sullivan, sometimes heralded as the Father of the Skyscraper. Sullivan could almost make this list based on who worked for him: He had at least one very famous architect serve as his chief draftsman for many years, an architect we'll encounter later on in this list. But Sullivan's impact went far beyond this one pupil.
Born in 1856, Sullivan worked with a variety of architectural firms, and as his career progressed, the buildings designed by those firms became increasingly lofty. A true believer (and by many accounts the originator) of the now common axiom "form follows function," Sullivan had no problem helping envision, design and build many a structure that soared above those of his contemporaries. Once the functional aspect was taken care of, Sullivan also had no qualms about adding rich ornamentation to the interiors and exteriors of he and his partners' unique projects.
As many an architect hesitated to transition to modern developments like steel structures and electrical lighting, Sullivan and his compatriots helped blaze the trail, while still respecting the tried-and-true properties of the commonly used materials of the day. On the next page, someone who followed in his footsteps, and pushed the boundaries even further ...