quality:corruption
Towers and the flèche

The two towers are 69 metres (226 ft) high. The towers were the last major element of the cathedral to be constructed. The south tower was built first, between 1220 and 1240, and the north tower between 1235 and 1250. The newer north tower is slightly larger, as can be seen when they are viewed from directly in front of the church. The contrefort or buttress of the north tower is also larger. The cathedral's main peal of bells is within these towers.

The south tower was accessible to visitors by a stairway, whose entrance was on the south side of the tower. The stairway has 387 steps, and has a stop at the Gothic hall at the level of the rose window, where visitors could look over the parvis and see a collection of paintings and sculpture from earlier periods of the cathedral's history.

The cathedral's flèche (or spirelet) was located over the transept. The original flèche was constructed in the 13th century, probably between 1220 and 1230. It was battered, weakened and bent by the wind over five centuries, and finally was removed in 1786. During the 19th-century restoration, Eugène Viollet-le-Duc recreated it, making a new version of oak covered with lead. The entire flèche weighed 750 tonnes.

Following Viollet-le-Duc's plans, the flèche was surrounded by copper statues of the twelve Apostles — a group of three at each point of the compass. In front of each group is a symbol representing one of the four evangelists: a winged ox for Saint Luke, a lion for Saint Mark, an eagle for Saint John and an angel for Saint Matthew. Just days prior to the fire, the statues were removed for restoration. While in place, they had faced outwards towards Paris, except one: the statue of Saint Thomas, the patron saint of architects, faced the flèche, and had the features of Viollet-le-Duc.

The rooster weathervane at the top of the flèche contained three relics: a tiny piece from the Crown of Thorns in the cathedral treasury, and relics of Saint Denis and Saint Genevieve, patron saints of Paris. They were placed there in 1935 by Archbishop Jean Verdier, to protect the congregation from lightning or other harm. The rooster with relics intact was recovered in the rubble shortly after the fire.