An amphitheater is an open-air venue used for entertainment, typically seating thousands of people. It is similar to a STADIUM, which is a large enclosed structure with tiered seating, but an amphitheater is usually more open and has a central stage. A COLISEUM is a large, OVAL-shaped amphitheater, while a THEATER is a building with a stage and seating for an audience. A FIELD is an open area of land, often used for sports or other activities, while a BOWL is a large, round, open-air STADIUM. A HALL is a large room or building used for meetings, concerts, or other events, and an OVAL is a shape that is rounded at the ends and flattened in the middle. An ARENA is a large, enclosed space used for sports or entertainment, and a COLOSSEUM is a large amphitheater, typically OVAL-shaped, used for public spectacles.