keystone
penut
The key stone is the stone placed at the apex of the arch, and prevents the two sides of the arch falling in and collapsing.
one example is in a bridge.
An extended arch is called a vault. Most tunnel are built using vaults. It's a bunch of arches put together.
I think its the Notre Dame ===================== The above is incorrect although I do not know the name of the arch you are referring to. You always see this arch during the end of the Tour de France cycling event and they refer to it often. Notre Dame is a gothic cathedral which has arches but this is not the large stone arch that you are asking about. ========================== L'arc de Triomphe
There are Eldon, Avendix, Sharpie, Agriland, Brown Stone, Ferguson, and Purple Arch.
a Keystone or Boss.
The key stone is the stone placed at the apex of the arch, and prevents the two sides of the arch falling in and collapsing.
the key stone is the stone that is at the top of an arch. It is this stone that absorbs the majority of the forces stabilizing the arch formed
Newport Stone Arch Bridge was created in 1853.
Lalino Stone Arch Bridge was created in 1870.
Pithole Stone Arch Bridge was created in 1899.
Tusten Stone Arch Bridge was created in 1896.
Stone Arch Bridge - Minneapolis - was created in 1883.
Hankins Stone Arch Bridge was created in 1905.
Stone and clay was used and packed to form the arch of Augustus. Their were two.
Key-stone.
Elm Street Stone Arch Bridge was created in 1900.