Pontcysyllte Aqueduct, nr Wrexham in Wales. One of the major engineering triumphs of Thomas Telford's remarkable career, The Pontcyslite Aquaduct carries the Shropshire Union Canal across the River Dee. The aquaduct is 127 feet above the valley floor
There's a million fascinating facts and figures about the London Underground, but this rarely seen photograph reminds us just what an engineering feat the construction process was. Here we see the creation of the Central Line in 1898.