Ziggurats were massive structures built in the ancient Mesopotamia

Mesopotamia

Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

n valley and western Iranian plateau

Iranian plateau

The Iranian plateau, or Iranic plateau, is a geological formation in Southwest Asia. It is the part of the Eurasian Plate wedged between the Arabian and Indian plates, situated between the Zagros mountains to the west, the Caspian Sea and the Kopet Dag to the north, the Hormuz Strait and Persian...

, having the form of a terraced step pyramid

Step pyramid

Step pyramids are structures which characterized several cultures throughout history, in several locations throughout the world. These pyramids typically are large and made of several layers of stone...

 of successively receding stories or levels.

Notable ziggurats include the Great Ziggurat of Ur

Great Ziggurat of Ur

The Ziggurat of Ur is a Neo-Sumerian ziggurat in what was the city of Ur near Nasiriyah, in present-day Dhi Qar Province, Iraq...

 near Nasiriyah

Nasiriyah

Nasiriyah is a city in Iraq. It is on the Euphrates about 225 miles southeast of Baghdad, near the ruins of the ancient city of Ur. It is the capital of the province of Dhi Qar...

, Iraq; the Ziggurat of Aqar Quf near Baghdad

Baghdad

Baghdad is the capital of Iraq, as well as the coterminous Baghdad Governorate. The population of Baghdad in 2011 is approximately 7,216,040...

, Iraq; Chogha Zanbil in Khūzestān

Khuzestan Province

Khuzestan Province is one of the 31 provinces of Iran. It is in the southwest of the country, bordering Iraq's Basra Province and the Persian Gulf. Its capital is Ahwaz and covers an area of 63,238 km²...

, Iran; and Sialk near Kashan

Kashan

Kashan is a city in and the capital of Kashan County, in the province of Isfahan, Iran. At the 2006 census, its population was 248,789, in 67,464 families....

, Iran.
Ziggurats were built by the Sumer

Sumer

Sumer was a civilization and historical region in southern Mesopotamia, modern Iraq during the Chalcolithic and Early Bronze Age....

ians, Babylon

Babylon

Babylon was an Akkadian city-state of ancient Mesopotamia, the remains of which are found in present-day Al Hillah, Babil Province, Iraq, about 85 kilometers south of Baghdad...

ians, Elam

Elam

Elam was an ancient civilization located in what is now southwest Iran. Elam was centered in the far west and the southwest of modern-day Iran, stretching from the lowlands of Khuzestan and Ilam Province, as well as a small part of southern Iraq...

ites, Akkad

Akkad

The Akkadian Empire was an empire centered in the city of Akkad and its surrounding region in Mesopotamia....

ians, and Assyria

Assyria

Assyria was a Semitic Akkadian kingdom, extant as a nation state from the mid–23rd century BC to 608 BC centred on the Upper Tigris river, in northern Mesopotamia , that came to rule regional empires a number of times through history. It was named for its original capital, the ancient city of Assur...

ns for local religions.