A coliseum is a large, open-air venue used for public events, particularly in ancient Rome. The most famous example is the Colosseum, which could hold tens of thousands of spectators. These structures were designed for various activities, including gladiatorial contests, animal hunts, and theatrical performances. Coliseums typically feature a circular or oval shape, allowing for good visibility from all seats. They often include tiered seating, an arena floor, and sometimes elaborate entrances and exits. Today, modern coliseums continue to host sports events, concerts, and other entertainment, reflecting their historical significance in public gatherings.