Karnak is the largest and most well developed complex of temples at Thebes, onetime capital of Ancient Egypt. For nearly 1,700 years, the leaders of Egypt felt it their duty to enhance existing temples or erect new ones at the famed site.

Archaeologists think that the first construction at Karnak took place about 3200 B.C., about the time that Narmer unified Lower Egypt and Upper Egypt and became the first pharaoh. Fragments of later construction date to dynasties slightly later. The majority of the building at Karnak, however, dates from about 2055 B.C. to about A.D. 100.

Karnak–or Ipet-isu and Nesut-Towi, as it was known–was filled with temples dedicated to the sacred god Amen and also to the gods Mut and Khonsu. Other gods honored at the site include Isis, Montu, Osiris, and Ptah.

Senusret I in the 19th Century B.C. is the first known builder at Karnak, many historians say. He followed by a few years Mentuhotep II, who united the Two Lands under Theban rule and built a mortuary complex across the river, at Deir el-Bahri.

The pharaohs most associated with construction at Karnak are those of the New Kingdom, and the first of those was Ahmose I, who organized the Thebes-driven rebellion against the Hyksos and contributed to the ongoing work at Karnak. Following in his footsteps were the even more famous Amenhotep III, Seti I, and Ramses II. The well-known female pharaoh Hatshepsut added twin obelisks at the entrance to the temple.

The Temple of Amen was a busy place, staffed by a great many priests who, as arbiters of the worship of the greatest god, had much power and wealth, so much so the pharaoh Akhenaten saw fit to move the royal capital to Akhetaten and close many of the temples to Amen. (Even so, he built a temple at Karnak–to Aten.) Other pharaohs were not so successful at reducing the priests' power.

Two peoples who had success in this area were the Assyrians and the Persians, who sacked Thebes in 666 B.C. and 525 B.C., respectively. Both times, however, the invaders did not destroy Karnak.

A later pharaoh, Amyrtaeus, ousted the Persians and restored home rule. He contributed to Karnak by adding an obelisk and a pylon; he also had built a wall around the site. Still later, the pharaoh Ptolemy IV added to the Karnak complex by having built an underground burial site dedicated to Osiris.

Many sources say that Karnak is still the largest religious building in the world. Some estimates say that just the main Karnak temple could house the famous Notre Dame Cathedral three times over. At Karnak today, the ruins cover 200 acres.

Unifying the complex are a number of pylons that lead into temples and courtyards, including the Hypostyle Court, a 50,000-square-foot area that is supported by 134 columns, each 72 feet tall and 11 feet in diameter. The temple grew into a complex that contained three sections, one each dedicated to the Theben Triad of Amen, Mut, and Khonsu.

The name Karnak is from the Arabic Khurnak, which means "fortified village."