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,
History of the world's tallest buildings a "building" as "(A) structure that is designed for residential, business or manufacturing purposes" and "has floors". Tall churches and cathedrals occupy a middle ground: their lower areas are regularly occupied, but much of their height is in bell towers and spires which are not. Whether a church or cathedral is a "building" or merely a "structure" for the purposes of determining the title of "world's tallest building" is a subjective matter of definition (this article treats churches and cathedrals as buildings). The Council on Tall Buildings and Urban Habitat based in Chicago uses three different criteria for determining the