 These allowed shelter from the elements, but still could be opened on a nice day.To be able to support the roof, most were closed in on all sides like multi-purpose and indoor parks, but as all retractable-roof parks except Rogers Centre are baseball only, every square foot does not need to be filled with seating, and there is plenty of room for open spaces or windows that look outside.Because the roof needs to go somewhere when not covering the field, a distinguishing characteristic of the retractable roof park is a large extension of the interior spaces to either one side of the field or both sides that the roof sits on when retracted.