Frontal view of the north entry, with "MONADNOCK" over the door; From 1880 Burnham & Root emerged as the principal designers of the new ten-storey skyscraper office buildings. In some two dozen subsequent structures in the city, the firm perfected 'raft' foundations to support tall buildings on the muddy Chicago soil, iron (and eventually steel) skeletal frames to lighten and expedite their construction, and a frank, unfussy treatment of façades in red brick, terracotta and sandstone to express this new technological creation. Burnham & Root designed the Monadnock Building at the south-west corner of Dearborn and Jackson Streets, with a brick exterior ornamented only by the elegant batter of its walls and cavetto cornice. When it was comple...