Editing Roman bridge (section)

=== Large river bridging ===
Roman engineers built stone arch or stone pillar bridges over all major rivers of the Empire save two: the [[Euphrates]], which lay at the frontier in the [[Roman–Persian Wars]], and the [[Nile]], the longest river in the world, which was bridged as late as 1902 by the British [[Old Aswan Dam]].<ref>{{harvnb|O'Connor|1993|pp=193–202 (Appendices A and B)}}

[[Help:Category|Categories]]</ref> The largest rivers to be spanned by solid bridges by the Romans were the [[Danube]] and the [[Rhine]], [[List of rivers of Europe|the two largest European rivers]] west of the [[Eurasian Steppe]]. The lower Danube was crossed by least two ([[Trajan's Bridge]], [[Constantine's Bridge (Danube)|Constantine's Bridge]]) and the middle and lower Rhine by four different bridges (the [[:de:Römerbrücke (Mainz)|Roman Bridge at Mainz]], [[Caesar's Rhine bridges]], the [[:de:Römische Brücken in Koblenz|Roman Bridge at Koblenz]], the [[:de:Römerbrücke (Köln)|Roman Bridge at Cologne]]). For rivers with strong currents and to allow swift army movements, [[pontoon bridge]]s were also routinely employed.<ref>{{harvnb|O'Connor|1993|pp=133–139}}</ref> Judging by the distinct lack of records of pre-modern solid bridges spanning larger rivers,<ref name="troyano" /> the Roman feat appears to be unsurpassed anywhere in the world until into the 19th century.