The sound and light show at Karnak runs several evenings per week, taking visitors on a walk through the illuminated temple complex as a recorded narration covers the history of ancient Thebes. The route goes through the main pylons and along the sacred lake, which is dramatically lit from below.
These shows are an acquired taste — the narration is earnest and the theatrical effects have not been updated for several decades — but the setting does most of the work. Walking through the Great Hypostyle Hall at night, with its 134 columns lit against a dark sky, is genuinely impressive in a way that the daytime visit is not, precisely because the crowds are gone and the scale is unmediated by tourists. Check the schedule and language at the ticket office on the day; shows are in multiple languages and times vary seasonally.