The Tar Tunnel is located on the north bank of the River Severn in the Ironbridge Gorge at Coalport, England. It is one of ten Ironbridge Gorge Museums attractions administered by the Ironbridge Gorge Museum Trust. The tunnel was a great curiosity in the eighteenth century and bitumen still oozes gently from the brick walls today. Bitumen's chief commercial use at the time was to treat and weatherproof ropes and caulk wooden ships, but small amounts were processed and bottled as 'British oil', a remedy for rheumatism.