The Karnak Temple Complex, commonly known as Karnak comprises a vast mix of decayed temples, chapels, pylons, and other buildings. Building at the complex began during the reign of Senusret I in the Middle Kingdom and continued into the Ptolemaic period, although most of the extant buildings date from the New Kingdom. The area around Karnak was the ancient Egyptian Ipet-isut The Most Selected of Places and the main place of worship of the eighteenth dynasty Theban Triad with the god Amun as its head. It is part of the monumental city of Thebes. The Karnak complex gives its name to the nearby, and partly surrounded, modern village of El-Karnak, 2.5 kilometres (1.6 miles) north of Luxor
The complex is a vast open-air museum, and the second largest ancient religious site in the world, after the Angkor Wat Temple of Cambodia. It is believed to be the second most visited historical site in Egypt; only the Giza Pyramids near Cairo receive more visits. It consists of four main parts, of which only the largest is currently open to the general public. The term Karnak often is understood as being the Precinct of Amun-Ra only, because this is the only part most visitors see. The three other parts, the Precinct of Mut, the Precinct of Montu, and the dismantled Temple of Amenhotep IV, are closed to the public. There also are a few smaller temples and sanctuaries connecting the Precinct of Mut, the Precinct of Amun-Re, and the Luxor Temple.
The Precinct of Mut is very ancient, being dedicated to an Earth and creation deity, but not yet restored. The original temple was destroyed and partially restored by Hatshepsut, although another pharaoh built around it in order to change the focus or orientation of the sacred area. Many portions of it may have been carried away for use in other buildings.
The key difference between Karnak and most of the other temples and sites in Egypt is the length of time over which it was developed and used. Construction of temples started in the Middle Kingdom and continued through to Ptolemaic times. Approximately thirty pharaohs contributed to the buildings, enabling it to reach a size, complexity, and diversity not seen elsewhere. Few of the individual features of Karnak are unique, but the size and number of features are overwhelming. The deities represented range from some of the earliest worshiped to those worshiped much later in the history of the Ancient Egyptian culture. Although destroyed, it also contained an early temple built by Amenhotep IV (Akhenaten), the pharaoh who later would celebrate a near monotheistic religion he established that prompted him to move his court and religious center away from Thebes. It also contains evidence of adaptations, using buildings of the Ancient Egyptians by later cultures for their own religious purposes.
One famous aspect of Karnak is the Hypostyle Hall in the Precinct of Amun-Re, a hall area of 50,000 sq ft (5,000 m2) with 134 massive columns arranged in 16 rows. 122 of these columns are 10 meters tall, and the other 12 are 21 meters tall with a diameter of over three meters.
The architraves on top of these columns are estimated to weigh 70 tons. These architraves may have been lifted to these heights using levers. This would be an extremely time-consuming process and also would require great balance to get to such great heights. A common alternative theory regarding how they were moved is that large ramps were constructed of sand, mud, brick or stone and that the stones were then towed up the ramps. If stone had been used for the ramps, they would have been able to use much less material. The top of the ramps presumably would have employed either wooden tracks or cobblestones for towing the megaliths.
There is an unfinished pillar in an out-of-the-way location that indicates how it would have been finished. Final carving was executed after the drums were put in place so that it was not damaged while being placed. Several experiments moving megaliths with ancient technology were made at other locations – some of them are listed here
The history of the Karnak complex is largely the history of Thebes and its changing role in the culture. Religious centers varied by region and with the establishment of the current capital of the unified culture that changed several times. The city of Thebes does not appear to have been of great significance before the Eleventh Dynasty and previous temple building here would have been relatively small, with shrines being dedicated to the early deities of Thebes, the Earth goddess Mut and Montu. Early building was destroyed by invaders. The earliest known artifact found in the area of the temple is a small, eight-sided temple from the Eleventh Dynasty, which mentions Amun-Re. Amun (sometimes called Amen) was long the local tutelary deity of Thebes. He was identified with the Ram and the Goose. The Egyptian meaning of Amun is, "hidden" or, the "hidden god]
Major construction work in the Precinct of Amun-Re took place during the Eighteenth dynasty when Thebes became the capital of the unified Ancient Egypt.
Thutmose I erected an enclosure wall connecting the Fourth and Fifth pylons, which comprise the earliest part of the temple still standing in situ. Construction of the Hypostyle Hall also may have begun during the eighteenth dynasty, although most new building was undertaken under Seti I and Ramesses II.
Almost every pharaoh of that dynasty has added something to the temple site. Merneptah commemorated his victories over the Sea Peoples on the walls of the Cachette Court, the start of the processional route to the Luxor Temple.
Hatshepsut had monuments constructed and also restored the original Precinct of Mut, the ancient great goddess of Egypt, that had been ravaged by the foreign rulers during the Hyksos occupation. She had twin obelisks, at the time the tallest in the world, erected at the entrance to the temple. One still stands, as the tallest surviving ancient obelisk on Earth; the other has broken in two and toppled. Another of her projects at the site, Karnak's Red Chapel, or Chapelle Rouge, was intended as a barque shrine and originally, may have stood between her two obelisks. She later ordered the construction of two more obelisks to celebrate her sixteenth year as pharaoh; one of the obelisks broke during construction, and thus, a third was constructed to replace it. The broken obelisk was left at its quarrying site in Aswan, where it still remains. Known as The Unfinished Obelisk, it demonstrates how obelisks were quarried
The last major change to Precinct of Amun-Re's layout was the addition of the first pylon and the massive enclosure walls that surround the whole Precinct, both constructed by Nectanebo I.
In 323 AD, Constantine the Great recognised the Christian religion, and in 356 Constantius II ordered the closing of pagan temples throughout the empire. Karnak was by this time mostly abandoned, and Christian churches were founded among the ruins, the most famous example of this is the reuse of the Festival Hall of Thutmose III's central hall, where painted decorations of saints and Coptic inscriptions can still be seen.