Thiers wall

The Thiers Wall is marked by the distinct, sweeping curve of the Boulevard des Marechaux that rings the edge of the eighteenth arrondissement. Built between eighteen forty-one and eighteen forty-four, this massive fortification system once encircled all of Paris with bastions and a deep moat. Adolphe Thiers insisted on its construction to protect the city from invading armies. By the time it was completed, the wall was already obsolete because of advancements in artillery range, and it was dismantled in the nineteen twenties.