As recently as 1950 Grimsby had the largest fishing fleet in the world. Cod wars and economic change put paid to the rich, dangerous trade, and now Grimsby docks handle cars instead of fish.
Grimsby’s most distinctive architecture is firmly associated with the docks.
The Custom House (1874) and the Dock Offices (Mills & Murgatroyd, 1885) remain in use, but the Victoria Flour Mills (Sir W A Gelder, 1889/1906), which was partly converted to apartments in the 1990s, is threatened by structural problems with its unconverted silo tower: http://www.victoriansociety.org.uk/news/grimsby-mill-tower-on-endangered-buildings-list.
The Grimsby Ice Company’s Ice House (1901), which could produce 1,250 tons of ice every 24 hours for direct loading into the trawlers, ceased production in 1990. Though it still contains historic refrigeration equipment of world importance, it is no longer watertight and regularly appears on at-risk registers: http://www.victoriansociety.org.uk/news/the-grimsby-ice-factory-gorton-street-the-docks-grimsby.
Most dramatic of all is the Dock Tower (James W Wild, 1851-2), its extreme height, 309ft, determined by the need to provide a head of hydraulic pressure, using a 30,000-gallon water-tank, by gravity alone.
The hydraulic machinery by Sir William Armstrong was the first to be applied to working dock gates: both sets of gates could be opened within 2½ minutes by two men.
The relatively little-known James Wild was well travelled, and brought his sketchbook ideas to Grimsby. Pevsner’s Buildings of England entry points out that “the tower…is straight from Italy [ie, Siena Town Hall], but the crowning minaret is oriental…”
Grimsby’s workaday architecture is too good to lose: http://www.victoriansociety.org.uk/news/council-inaction-worse-for-grimsbys-image-than-cha-baron-cohen-film.
Update: A recent article in the Grimsby Telegraph, June 8th 2017, illustrates the extent of the decay, and the beginning of the restoration, of the Victoria Mills: http://www.grimsbytelegraph.co.uk/news/grimsby-news/unveiling-marks-start-another-100-100989.
Further update: The designation of conservation area status for the dockland area known as the Kasbah is a welcome indication that Grimsby’s industrial heritage is receiving attention: https://www.nelincs.gov.uk/securing-kasbahs-future.
Another update: The Grimsby Telegraph‘s ‘Stop the Rot’ campaign itemises the extent of the rich heritage at risk in Grimsby and Cleethorpes: https://www.grimsbytelegraph.co.uk/news/grimsby-news/stop-rot-33-pieces-history-1718435.