The Opera House is a large public building designed for performances of opera, theater, and other artistic events. It typically features a stage, seating for an audience, and advanced acoustics to enhance sound quality. Many famous cities have their own opera houses, which serve as cultural landmarks. One of the most iconic examples is the Sydney Opera House in Australia, known for its unique sail-like design. Opened in 1973, it hosts a variety of performances, including concerts and ballets, and is a UNESCO World Heritage Site, attracting millions of visitors each year.