The Sacred Lake at Karnak is a large rectangular pool surrounded by storehouses and priests' quarters on three sides, with the main temple complex behind. Measuring roughly 120 by 77 metres, it is the largest surviving sacred lake in Egypt. In antiquity it was kept permanently full from the Nile by underground channels and was used for ritual purification and the sailing of sacred barques.
Today the lake is the setting for the evening sound and light show, which uses it effectively as a reflective surface for the illuminated pylons behind. During the day, the lake is worth visiting for the contrast it provides — a rectangular mirror of water in the middle of a stone desert, surrounded by the architecture of 4,000 years of temple building. Rest here in the shade of the colonnades and take in the full scale of Karnak before heading back out through the pylons.