The Exhibition Grounds, which include the site for the Empire Stadium as well as for the British Empire Exhibition, comprise an area of roughly 216 acres. The north-eastern boundary runs parallel with the Metropolitan Railway, and the North Entrance to the Exhibition is only a few yards south of Wembley Park Railway Station bridge. At or near the station the mean level is about 110 feet above O.D.; but the surface of the ground is uneven, and rises to 210 feet above O.D. at Wembley Hill, outside the south-western extremity of the Exhibition area. The Wealdstone Brook runs irregularly along the northern boundary in an easterly direction in the neighbourhood of the Amusement Park, but for the sake convenience its regular course has been slightly diverted at this point and an old lake filled up. The main sections to be described are north of the brook.