The archaeological interest of Eridu is one vertical cut. Digging down beneath the platform of the unfinished ziggurat, the excavators of the late 1940s found not one temple but a long series of them, each built on the levelled ruins of the last, on the same spot, running from a substantial late building at the top to a small single-room structure near the bottom of the mound. The recurring furniture, an offering table and a niche in one wall, appears again and again down the sequence.
Nothing else in Mesopotamia shows the point so plainly. A sanctuary is a place before it is a building, and the building is periodically demolished and replaced without the place moving. Everything Mesopotamian religion does with foundations, with the ritual of rebuilding a temple exactly where it stood, and with the pride kings took in restoring a house to its old plan, is visible in that section.
What the section cannot settle is whether the rebuilding was continuous. Three seasons of excavation in the 1940s, published long afterward, recorded the sequence with the methods of their day. There is no radiocarbon series running through it, and whether the intervening deposits contain occupation gaps is not established. Cult on the same spot over a very long stretch is certain; unbroken cult by a continuous population is not, and the atlas records that as an open question rather than repeating the stronger claim, which is often made.
The site is protected within a World Heritage property inscribed in 2016 together with Ur and Uruk.