title: Neath and Tennant Canal
context: The Neath and Tennant Canals are two independent but linked canals in South Wales that are usually regarded as a single canal. The Neath Canal was opened from Glynneath to Melincryddan, to the south of Neath, in 1795 and extended to Giant's Grave in 1799, in order to provide better shipping facilities. With several small later extensions it reached its final destination at Briton Ferry. No traffic figures are available, but it was successful, as dividends of 16 per cent were paid on the shares. The canal was 13.5 miles (21.7km) long and included 19 locks.
question: How long are the Neath and Tennant Canals?
answers: 13.5 miles