Pons Londinii
About
The original Roman timber bridge across the Thames, close to today's London Bridge, around which Londinium's settlement first grew around 47–50 CE. Roman engineers rebuilt the timber structure periodically throughout the occupation, but a bridge stood continuously at this crossing from the mid-1st century CE onward. It carried traffic straight into the heart of the growing port town.
What happened here
Piers are set on cofferdams — a ring of driven piles, pumped dry, filled with concrete that sets under water. They are built with a cutwater pointing upstream to split the current and the ice. The span above may be stone arches or timber on stone, and timber is not a poor relation: it is cheaper, faster, and replaceable. Roads approach on an embankment so the crossing stays level. Tolls are common, shrines at either end are usual, and the inscription names whoever paid. Floods are the enemy; a bridge is inspected after every big one, and the scour around the piers is packed with rubble. A bridge fixes a town's position for a thousand years, which is why so many are still standing.
Sources
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →