Alexandria's grand belle-époque opera house, on Tariq al-Horreya near the city centre. The building is a confection of neoclassical and rococo elements with a fully restored interior — gilded plasterwork, frescoed ceiling, plush red seats, and excellent acoustics for a theatre of its size (around 600 seats).
The Opera House runs a full season of opera, ballet, classical music, and Egyptian theatre — typically October through May. Tickets are extremely cheap by international standards (often under $10), and the programme is well worth checking even for a single evening. Even if you cannot catch a performance, the exterior is one of the better European-era facades in the city and the lobby is open to visitors during business hours.