Linked from
The 18 pages that link to Flying buttress, each with the reason it gives.
Gothic architectureBroader topic: It braced tall nave walls while leaving room for large windows.
ArchRelated: It counters the lateral thrust of Gothic arches and vaults from outside the building.
Notre-Dame de ParisBroader topic: These supports help stabilize the cathedral’s high stone vaults.
Pointed archRelated: It carries thrust from elevated arches and vaults to outer supports.