That was to keep people in, not keep people out.
Of the walls meant to keep people out, I can think of just two. The Maginot Line and the Great Wall of China.
Hadrian's Wall, the Wall of Antoninus Pius (just a few miles north of Hadrian's, really an earthworks and impediment to wagons and carts), the Limes Germanicus of Domitian (built to connect the Rhine and Danube frontiers and shorten the Roman defensive lines considerably), and the Dark Ages Limes Sorbicus built in Germany against the Slavic Sorbs by iirc Charlemagne or his sons. There was also Offa's Dyke in western England, built by the Saxons against the Welsh Britons.
In modern times, besides the Maginot Line, there were also the Belgian Leopold Line and the German Siegfried Line facing both; and during the war the Germans built two substantial fortification-lines, one in southern Russia and one (maybe two) in central Italy. Also, the Israeli Bar-Lev Line along the Suez Canal in the late 1960's, a continuous line of sandbag-and-earthworks fortifications broken down by the Egyptians in 1973 during the Yom Kippur War.
There are some others. I think the Finns built one either before or after the Winter War facing the Russians in Karelia, in southeastern Finland; I don't remember what it was called. During WW I the Germans built a large fallback fortification system on the Western Front called the Hindenburg Line in 1917 or 1918. And of course the two 20th-century "DMZ's" in Korea and Vietnam were heavily fortified and tricked out with Igloo White and various other sensor systems and could be compared to any of the above.