Laon was also unusual because of its five towers; two on the west front, two on the transepts, and an octagonal lantern on crossing. Laon, like most early Gothic cathedrals, had four interior levels. Laon also had alternating octagonal and squar piers supporting the nave, but these rested upon massive pillars made of dreamlike sections of stone, giving it greater harmony and a greater sensation of length. The new cathedral was unusual in form; The apse on the east was flat, not rounded, and The choir was exceptionally long, nearly as long as the nave.. Another striking feature of Laon Cathedral were the three great rose windows, one on the west facade and two on the transepts. (Only the west and north windows still remain). Another unusual feature at Laon is lantern tower at the transept crossing, most likely inspired by the Norman Gothic abbey churches in Caen. Notre Dame de Paris was the largest of the Early Gothic cathedrals, and marked the summit of the Early Gothic in France. It was begun in 1163 by the Bishop Maurice de Sully with the intention of surpassing all other existing churches in Europe. The new cathedral was 122 meters long and 35 meters high, eleven meters higher than Laon Cathedral, the previous tallest church. It featured a central nave flanked by double collaterals, and a choir surrounded by a double ambulatory, without radiating chapels. (The current chapels were added between the buttresses in the 14th century). The builders covered the interior of the Cathedral with six-part vaults, but unlike Sens and other the earlier cathedrals they did not use alternating piers and columns to support them. The vaults were supported instead by bundles of three uninterrupted slender columns which were received by rows massive pillars with capitals decorated with classical decoration. This gave the nave greater harmony. The original elevation of Notre Dame had four levels, This was reduced to three in the 13th century, when it was decided that the interior was too dark, but it was returned to four levels around the transept during the restoration by Viollet-le-Duc. The flying buttress made its first appearance in Paris in the early 13th century, either at Notre Dame, or perhaps earlier in the Abbey of Saint-Germain-des-Pres. The buttresses, in the form of half-arches, reached from the heavy buttresses outside the nave, over the top of the tribunes, and pressed directly against the upper walls of the nave, countering the outward thrust from the vaults.