The classic bullring is an enclosed, roughly circular amphitheatre with tiered rows of stands that surround an open central space.
The open space forms the arena or ruedo, a field of densely packed crushed rock (albero) that is the stage for the bullfight.
Also on the ground level, the central arena is surrounded by a staging area where the bullfighters prepare and take refuge, called the callejón (alley).
In regular places, the wall is pushed outwards leaving splits (burladero, from burlar: to evade, to dodge) that allow the bullfighters to go in the arena and to take refuge but are too narrow for the bull.
The earliest examples are found in the Sierra de Huelva, which was the destination of transhumance routes from León, who brought some of their culture with them, including the feast of San Mamés, mostly associated with northern Spain.
It was precisely in the hamlet of San Mamés, between Aroche and Rosal de la Frontera, where the oldest documented coso was built in 1599.
[4] The oldest plaza still in use, Las Virtudes in Santa Cruz de Mudela, Ciudad Real, dates from 1641 and has a square shape.