Swansea Mawr are able to speak Welsh, as can 38% of the ward of Pontarddulais. Clydach, Kingsbridge and Upper Loughor all have levels of more than 20%. By contrast, the urban St. Thomas has one of the lowest figures in Wales, at 6.4%, a figure only barely lower than Penderry and Townhill wards. Local produce includes: The city has three Grade One listed buildings: Swansea Castle, the Tabernacle Chapel, Morriston and the Swansea Guildhall. Swansea Castle was an impressive building occupying a strategic position above the River Tawe. The ruins that are visible today date from the late 13th and early
Swansea Canal culvert through large metal grids. There was a short tramway from below the lock to Ynys-penllwch Graig-ola Colliery. Mond Lock was next, with the B4603 crossing the tail of the lock. Below the bridge is the Mond Nickel Works, set up in 1900 after the chemist Dr Ludwig Mond discovered a process for producing pure nickel. Nickel ore was imported from Canada, and the site was chosen because there were supplies of anthracite coal, water, transport links to Swansea, and an available labour force. The canal crosses the Lower Clydach River on an aqueduct, which discharges water into the river,