Ekur (É.KUR, E2.KUR, E-kur) is a Sumerian term meaning "mountain house". It is the assembly of the gods in the Garden of the gods, parallel in Greek mythology to Mount Olympus and was the most revered and sacred building of ancient Sumer.
There is a clear association of Ziggurats with mountain houses. Mountain houses play a certain role in Mesopotamian mythology and Assyro-Babylonian religion, associated with deities such as Anu, Enlil, Enki and Ninhursag. In the Hymn to Enlil, the Ekur is closely linked to Enlil whilst in Enlil and Ninlil it is the abode of the Annanuki, from where Enlil is banished. The fall of Ekur is described in the Lament for Ur. In mythology, the Ekur was the centre of the earth and location where heaven and earth were united. It is also known as Duranki and one of its structures is known as the Kiur ("great place").Enamtila has also been suggested by Piotr Michalowski to be a part of the Ekur. A hymn to Nanna illustrates the close relationship between temples, houses and mountains. "In your house on high, in your beloved house, I will come to live, O Nanna, up above in your cedar perfumed mountain".
The Tummal Inscription records the first king to build a temple to Enlil as Enmebaragesi, the predecessor of Gilgamesh, around 2500 BC. Ekur is generally associated with the temple at Nippur restored by Naram-Sin of Akkad and Shar-Kali-Sharri during the Akkadian Empire. It is also the later name of the temple of Assur rebuilt by Shalmaneser I. The word can also refer to the chapel of Enlil in the temple of Ninimma at Nippur. It is also mentioned in the Inscription of Gaddas as a temple of Enlil built "outside Babylon", possibly referring to the Enamtila in west Babylon. It is used as part of such Sumerian phrases as e-kur-igi-gal; "House, Mountain Endowed with Sight", e-kur-igi-bar-ra; "House, Mountain which Sees", e-kur-mah; "House, Exalted Mountain", e-kur-mah; a temple of Ninazu, e-kur-me-sikil; "House, Mountain of Pure Mes (laws or judgement)" - a sanctuary of Ishtar, e-kur-nam-ti-la; "House, Mountain of Life", e-kur-ni-zu; "House, Fearsome Mountain" - the sanctuary of Ninlil at hursag-kala-ma (likely a later name of e-hursag-kalam-ma), etc.