Historic navigation locks at Bingley, Foxton, Caen Hill, Hatton, Neptune Staircase, Ottawa, Peterborough, Kirkfield, Rogny and Fonseranes. An engineering selection, not a worldwide ranking of age or size. Peterborough and Kirkfield are hydraulic boat lifts, not ordinary lock staircases. The Foxton photo shows its upper five-chamber flight; the complete complex comprises two such flights. Caen Hill has sixteen main steep locks within an overall flight of twenty-nine. Hatton wide concrete chambers reflect1930s reconstruction. Neptune Staircase is seen descending towards Loch Eil. Rogny is a disused dry staircase bypassed by a later canal route. Fonseranes originally had eight chambers and nine gates; six chambers form the later route. The source does not specify a date for its photograph. Other photos date from2007-2021. Archival views do not establish present condition, boat operations or visitor access. Authors and open licenses are listed below. Bingley Five Rise Locks: John Darch; CC BY-SA 2.0; https://creativecommons.org/licenses/by-sa/2.0/; https://commons.wikimedia.org/wiki/File:Bingley_Five_Rise_Locks_-_geograph.org.uk_-_1083371.jpg; resized and fitted to portrait frame; derived image retains the source license. Foxton Locks: Roger Kidd; CC BY-SA 2.0; https://creativecommons.org/licenses/by-sa/2.0/; https://commons.wikimedia.org/wiki/File:Upper_staircase_at_Foxton_Locks%2C_Leicestershire_-_geograph.org.uk_-_5893114.jpg; resized and fitted to portrait frame; derived image retains the source license. Caen Hill Locks: Alinangel; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/; https://commons.wikimedia.org/wiki/File:Caen_Hill_locks_Devizes.jpg; resized and fitted to portrait frame; derived image retains the source license. Hatton Locks: Stephen McKay; CC BY-SA 2.0; https://creativecommons.org/licenses/by-sa/2.0/; https://commons.wikimedia.org/wiki/File:Hatton_Locks_-_geograph.org.uk_-_4912909.jpg; resized and fitted to portrait frame; derived image retains the source license. Neptune Staircase: Daniel Kraft; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0/; https://commons.wikimedia.org/wiki/File:Neptune%27s_Staircase_20211023.jpg; resized and fitted to portrait frame; derived image retains the source license. Ottawa Locks: Mhsheikholeslami; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/; https://commons.wikimedia.org/wiki/File:Ottawa_Locks_at_Colonel_By_Valley-Rideau_Canal-_Ottawa-Ontario-5727-20131011.jpg; resized and fitted to portrait frame; derived image retains the source license. Peterborough Lift Lock: D. Gordon E. Robertson; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0/; https://commons.wikimedia.org/wiki/File:Peterborough_Lift_Lock%2C_2012.jpg; resized and fitted to portrait frame; derived image retains the source license. Kirkfield Lift Lock: The Cosmonaut; CC BY-SA 2.5 ca; https://creativecommons.org/licenses/by-sa/2.5/ca/; https://commons.wikimedia.org/wiki/File:Kirkfield_Lift_Lock_panorama.jpg; resized and fitted to portrait frame; derived image retains the source license. Rogny Seven Locks: Jean-Christophe BENOIST; CC BY 4.0; https://creativecommons.org/licenses/by/4.0/; https://commons.wikimedia.org/wiki/File:Rogny_-_Les_sept_%C3%A9cluses.jpg; resized and fitted to portrait frame; derived image retains the source license. Fonseranes Locks: Ad Meskens; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0/; https://commons.wikimedia.org/wiki/File:Fonseranes_2.jpg; resized and fitted to portrait frame; derived image retains the source license.