An arch bridge built of granite stones, Rathnapura, Sri Lanka

Bridges built of stones were an innovation, pre-dating the Roman times. The arch with the 'key-stone', supported the load over a waterway. When railways with their heavy steam engines appeared in the latter part of the nineteenth century, cheaper alternatives to the stone bridges had to be found. It was the French engineer Eiffel, who pioneered the building of railway bridges with steel girders. In Sri Lanka we have quite a few old stone bridges with arches, built by the British. The above is one of them seen in the Rathnapura district.