Mareth Line - Credit: Wikimedia Commons
The Mareth Line was a system of fortifications built by France in southern Tunisia in the late 1930s. The line was intended to protect Tunisia against an Italian invasion from its colony in Libya. The line occupied a point where the routes into Tunisia from the south converged, leading toward Mareth, with the Mediterranean Sea to the east and mountains and a sand sea to the west. Read more on Wikipedia
Source: en.wikipedia.org