(photo opposite)
The flying buttresses of the nave are characteristic of the great Gothic period.
Built of massive masonry, each consists of two superposed arches, one above and the other below the point of abutment of the ogival arches of the great nave.
These flying buttresses provide a counter-thrust which partly annuls that of the vault.
The remainder is taken by the massive buttresses surmounted by pinnacles and turrets, the latter preventing them from giving way under the continual thrust of the flying-buttresses.
