The Pontcysyllte Behemoth

The Pontcysyllte Aqueduct, a wonder from 1805, is a navigable structure that carries the Llangollen Canal across the River Dee in Wales. Spanning a width of 3.7 metres (12 feet), it's not only the longest aqueduct in Britain but also the highest canal aqueduct worldwide. Initially, the structure was envisioned as part of the Ellesmere Canal, an ambitious engineering project aiming to establish a commercial connection between the River Severn at Shrewsbury and the Port of Liverpool on the River Mersey.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons