An aisle is, in general, a space for walking with rows of seats on both sides or with rows of seats on one side and a wall on the other. Aisles can be seen in airplanes, certain types of buildings, such as churches, cathedrals, synagogues, meeting halls, parliaments and legislatures, courtrooms, theatres, and in certain types of passenger vehicles. Their floors may be flat or, as in theatres, stepped upwards from a stage. Aisles are distinguished from corridors, hallways, walkways, footpaths/pavements (American English sidewalks), trails, paths and (enclosed) "open areas".