- Ancient open-air theaters in Cornwall that were used to performannual medieval mystery plays. They were carved into hillslopes to allow a large number of spectators to face the central actingarea. An unusual feature was a trench used by actors for quick entrances.Documents suggest that the eastern end of the 'playing-place' wasused to represent Heaven while Hell was to the north. Cornish Roundswere used for performances until the 17th century. In 1968 the cycleof Cornish mystery plays was given at the Piran Round, Perranporth,by drama students from Bristol University, who used original stagingmethods.