This story begins in 1800, with the need for a lighthouse on Bell Rock off the Firth of Forth in Scotland. The account of how this was built is interwoven with the work of Richard Trevithick perservering at the same time in Cornwall on steam engines, road carriages and locomotives. Thomas Telford's and John Rennie's work as civil engineers is similarly intercut with the emergence of George Stephenson in the north of England and Marc Brunel in the south: as Stephenson completes the Stockton-Darlington railway, Brunel starts work on his tunnel under the Thames. Both men have talented sons roughly the same age, Isambard Kingdom Brunel and Robert Stephenson, who in the 1830s, along with Joseph Locke, come to dominate the engineering scene. Their railways are expressions of the nation's industrial might that the engineers had themselves made possible.