Charles Zeller Klauder (February 9, 1872 – October 30, 1938) was an American architect best known for his work on university buildings and campus designs, especially his Cathedral of Learning at the University of Pittsburgh, the first educational skyscraper. Biography Born in Philadelphia, Pennsylvania, Klauder was the son of Louis and Anna Koehler Klauder, who had immigrated to Philadelphia from Germany. He studied architecture at the School of Industrial Art at the Pennsylvania Museum. At age 15, he entered the office of Theophilus Parsons Chandler, Jr. Beginning in 1893 he worked for prominent Philadelphia architectural firms, including Wilson Brothers & Company, Cope & Stewardson, and Horace Trumbauer. In 1900, Klauder became chief draughtsman for Frank Miles Day & Brother, which led to a 1911 partnership, and the firm's eventual renaming as Day & Klauder. Klauder continued the firm after Day's 1918 death. Klauder teamed with the English-born Day to design some of the nation's most influential and distinguished campus buildings during the heyday of university expansion in the early 20th century. Along with Cope & Stewardson, Day & Klauder may be credited with the invention of the Collegiate Gothic idiom in American architecture. Their early work at Princeton and Cornell universities set the standard for dormitory and classroom designs in the Ivy League. Klauder extended the Gothic idiom during the 1920s to incorporate elements of Art Deco abstraction and modern building technology. He created campus plans for the University of Colorado (1917) in Boulder, St Paul's School in Concord, NH, Pennsylvania State University at University Park, and Concordia Seminary in St Louis, MO. His work at Princeton included dining halls (1913), Dickinson Hall (1929), dormitories (1921), the Holder group (1928), and the university's second library (1927). Several of his landmark Neo-Gothic buildings at the University of Pittsburgh are the Cathedral of Learning, Heinz Memorial Chapel and the Stephen Foster Memorial. The Cathedral of Learning, upon its completion, was the tallest educational building in the world, and today it ranks behind only a tower at Moscow University. It is also listed on the National Register of Historic Places. The Marks Scout Resource Center at 22nd and Winter Streets in Philadelphia was built in 1929. Klauder designed the building in the Beaux Arts style. Klauder considered his greatest achievement to be the Commons Room of the Cathedral of Learning. The Commons Room is a fifteenth-century English perpendicular Gothic-style hall that covers half