Karnak is less a building than an accumulation: the principal state sanctuary of Egypt, extended by pharaoh after pharaoh for some two millennia until it became the largest religious complex the ancient world produced.
The house of Amun-Ra
The core precinct belonged to Amun-Ra, the hidden creator god fused with the sun, who rose from a local Theban deity to the supreme god of the New Kingdom empire. His temple owned vast estates and worked as an economic and political power in its own right; the priesthood of Amun eventually rivalled the crown. Two further walled precincts honoured his consort Mut and the war god Montu. Because each ruler added rather than replaced, Karnak preserves a stratified record of Egyptian religious history, including the brief erasure and later restoration of Amun during and after the reign of Akhenaten.
The Great Hypostyle Hall
The most famous space, built chiefly under Seti I and Ramesses II in the Nineteenth Dynasty, is a forest of 134 columns over some 5,000 square metres, the tallest rising about 21 metres, once roofed and dim, carved and painted throughout. The architecture enacted a cosmology: the columns are papyrus stalks, the floor the primordial marsh, the whole a model of the ordered world emerging from chaos.
Procession and afterlife
Karnak was joined to the temple of Luxor to the south by an avenue of sphinxes along which the god's image travelled in the annual Opet festival, and across the river to the royal mortuary temples. Public worship did not enter the inner sanctuary; the cult image was tended by priests and shown to the people only in procession. The temples fell out of use after the end of Egyptian religion in late antiquity. The site is now an open-air museum and a centre of Egyptological excavation.