Aden became the capital of the new People's Republic of South Yemen which, in 1970, was renamed the People's Democratic Republic of Yemen. With the unification of northern and southern Yemen in 1990, Aden was no longer a national capital but remained the capital of Aden Governorate which covered an area similar to that of the Aden Colony.
The Cisterns of Tawila, or the Tawila Tanks, are the best-known historic site in Aden, Yemen. The site consists of a series of tanks of varying shape and capacity. They are connected to one another and located in Wadi Tawila to the southwest of Aden’s oldest district, Crater.
Sira Fortress is a military site in Aden, Yemen. The original fortress dates to the 11th century, and is still in use today by the Yemeni military. The fort is located on Sira Island, a rocky and tall volcanic outcropping which dominates the old harbor of Aden.