The flying buttresses of Notre-Dame de Paris.

Flying buttress above the heart of the Cathedral of Coutances.

A 360 ° in the middle of flying buttresses of the church of St. Eustache in Paris.

Vertical pan of the flying buttresses of the church of St. Eustache in Paris.

The flying buttresses of the cathedral of Meaux.

There is so many flying buttress, they can't put anymore!

The empty tower at the back on the right helps to support the main church structure.

On the roof of the cathedral of Chartres.

Stained-glass were replaced by wood during the refection of the cathedral.

There are statues of saints in the niches at the bottom of the buttresses. On the left side, a niche remained empty because you can not see inside the ground. This is optimization!