Birkenhead is a town in the Metropolitan Borough of Wirral, Merseyside, England; historically, until 1974, in Cheshire. It is on the Wirral Peninsula, along the south bank of the River Mersey, opposite the city of Liverpool. At the 2011 census, it had a population of 88,818. Birkenhead Priory and the Mersey Ferry were established in the 12th century. In the 19th century, Birkenhead expanded greatly as a consequence of the Industrial Revolution. Birkenhead Park and Hamilton Square were laid out as well as the first street tramway in Britain. The Mersey Railway connected Birkenhead and Liverpool, with the world's first tunnel beneath a tidal estuary, and the shipbuilding firm Cammell Laird and a seaport were established. In the second half of the 20th century, the town suffered a significant period of decline, with containerisation causing a reduction in port activity. The Wirral Waters development is planned to regenerate much of the dockland.