As a strategically located seat of European power, Paris was a prized target for foreign invaders. Consequently, it became one of the most heavily fortified cities in Europe and the world. Though many of the fortifications have been destroyed, demolished, or hidden behind civil and religious architecture, they have left their imprint on the city, both physically (with an outline still visible in the city’s thoroughfares) and historically. To understand the history of Paris–and indeed, of France as a whole–one must understand the history of the fortifications. This heavily illustrated history begins with the period from 300 BC to 987 AD, ranging from the Gallic period through that of the Carpetians. Part 2 looks at the Medieval era (987-1512), a growth period for the city marked by the enceinte of Philippe Auguste, the reign of Louis VIII and Louis IX, the establishment of the Louvre and the Bastille, the Hundred Years’ War, and the development of gunpowder and artillery. Bastioned fortifications (1512-1874) are the focus of part 3. It was in this era that Paris modernized its defenses, Louis XIV and Louis XV reigned, the city was transformed by Baron Georges Hausmann and Napoleon III, and the Franco-Prussian War was fought. Modern fortifications (1874-1944) are detailed in part 4, ranging from the building of the second Parisian ring of polygonal forts to the end of World War II.