The towers of cathedrals were usually the last part of the structure to be built. Since cathedral construction usually took many years, and was extremely expensive, by the time the tower were to be built public enthusiasm waned, and tastes changed. Many projected towers were never built, or were built in different styles than other parts of the cathedral, or with different styles on each level of the tower. At Chartres Cathedral, the south tower was built in the 12th century, in the simpler Early Gothic, while the north tower is the more highly decorated Flamboyant style. Chartres would have been even more exuberant if the second plan had been followed; it called for seven towers around the transept and sanctuary.