In architecture, an atrium (plural: atria or atriums) is a large open air or skylight covered space surrounded by a building. Atria were a common feature in Ancient Roman dwellings, providing light and ventilation to the interior. Modern atria, as developed in the late 19th and 20th centuries, are often several stories high and having a glazed roof or large windows, and often located immediately beyond the main entrance doors (in the lobby).
