Spire spires were an astounding architectural innovation, beginning with the early fourteenth-century spire at Freiburg Minster, in which the pierced stonework was held together by iron cramps. The openwork spire, according to Robert Bork, represents a "radical but logical extension of the Gothic tendency towards skeletal structure." The organic skeleton of Antoni Gaudi's phenomenal spires at the Sagrada Família in Barcelona represent an outgrowth of this Gothic tendency. Designed and begun by Gaudi in 1884, they were not completed until the 20th century. In England, "spire" immediately brings to mind Salisbury Cathedral. Its 403-foot (123-m) spire, built between 1320 and 1380,
Cathedral of Learning deliver the stone on schedule, so construction was delayed, and work began on the higher stories. When construction started on the Cathedral of Learning in 1926, it was the tallest building in Pittsburgh, although the Gulf Tower (1932) was completed and surpassed it by the time the Cathedral of Learning was officially dedicated in June 1937. Today, it remains the tallest educational building in the Western hemisphere, the second tallest university building in the world behind the 36 story, 240 m (including a 57 m spire) Moscow State University main building completed in 1953, and the fourth tallest educational building