Also called an emergency room, or operating room.

Operating Theatre's were so-called in England because they were semi-circular amphitheatres, often with high-raked seating (or standings) to allow students to observe medical operations.

The Old Operating Theatre (1822) in London is one of the oldest. It is a similar age to the Etherdome in Boston (1824.

dissecting theatres also exist in Padua and Upsalla