The theatre at Djemila was built into the hillside in the usual Roman fashion, using the natural slope for the seating cavea. It could hold several thousand spectators and was the cultural heart of the city — a venue for theatre, public readings, and the various ceremonies that structured Roman civic life.
The stage building (scaena) no longer stands to its full height, but the semicircular orchestra, the lower seating rows, and the structural walls of the cavea are substantially intact. The view from the upper seating rows, looking out over the ruins and the mountain valley beyond, is one of the finest vantage points on the site.
Occasional cultural events are held in the theatre during summer, reviving its original function. Ask at the ticket office whether anything is scheduled during your visit.