A Day in the 4th & 5th

Name the architectural structure which transmits lateral forces (pushing a wall outwards) through a segmental arch and vertical block.

I met my sister by the Notre Dame.





We decided to walk towards Place des Vosges to explore the area:


After lunch at Chez Pierro on Rue de Birague, we met up with my sister's friend at École Normale Supérieure, where the cafeteria staff was on strike:


So we had a picnic by the Seine!


If you answered with Flying Buttresses at the beginning...
*high five!*

^much easier to shoot from a distance!