A rough photogrammetry capture of the road bridge called Holborn Viaduct over Farringdon Street, London with stairwells in each corner. Model cross-sectioned just above the height of the bridge. Some of the the gates under the bridge are access points to the cable and sewer tunnels under this part of London. Under Farringdon Street is the River Fleet, the valley of which created the need for the bridge itself. Date: 1860s https://en.wikipedia.org/wiki/Holborn_Viaduct 4192 photos taken in June 2020 with a Sony a6000 and processed in Agisoft Metashape (in late 2020).