Located in the province of Batna,Timgad was an ancient Roman city built by the Emperor Trajan. It ceased to be inhabited after the 8th century. The triumphal arch, called the "Arch of Trajan, or " survived the test of time,and was finally renovated in 1900. The theater is also in beneficial condition, and is still used for modern music shows. The city was added to UNESCO's world heritage list in 1982.
Source: atlasobscura.com