A huge enlargement of an old map of Brigg fills an entire wall in one of the town's pubs today.
Scores of customers pass it at the back of Wrawby Street's Black Bull as they make their way from the beer garden towards the bar.
The map does not carry a date, and at first glance it appears to be late 19th century (Victorian) or very early 20th century (Edwardian).
However, closer inspection by those who know something about Brigg's history will conclude that it was drawn up much later.
The railway line is accompanied by the initials LNER - standing for London North Eastern Railway.
It was founded in 1923 when various companies amalgamated.
Also present on the map are Hawthorn Avenue - completed in 1930 - and the Newlands housing estate and Brigg Girls' High School on Wrawby Road (all buildings dating back to 1936).
The former Workhouse is marked on the map as a Public Assistance Institution. In the 1930s these were administered by local government - replacing Boards of Guardians.
The LNER, and other private railway companies, were phased out when nationalisation created British Railways (BR) on January 1, 1948. So the map must have been drawn before then.
We can narrow things down somewhat by considering that local map creation for public sale was highly unlikely during the Second World War (1939-1945) because of the threat of German invasion and concerns about enemy spies being parachuted into the countryside.
Roadside directional signs containing place names were removed so they did not assist any Germans seeking out airfields and military installations.
Therefore, we are left with 1936-39 as the likely timescale for this map.
It is worthy of close study as it shows all the town centre courtyards while many of their residential cottages, offering precious few mod cons, were still occupied by families.
Courtyard dwellers in the late 1930s were encouraged to relocate to the Newlands estate by Brigg Urban District Council, which built semi-detached homes to rent.
Brigg UDC bought up areas within the courtyards as they became available - eventually clearing the lot and deciding, in the early 1970s, to put up a parking lot.
Today this remains the town's main car park - accessed from the suitably named Old Courts Road.
Off Bridge Street, near today's Peacock & Binnington premises, the 1930s map shows Ancholme Foundry (indicated as disused).
However, the Victoria Iron Works (close to Engine Street and Barnard Street) does not have the same status given to its entry.
Part of Scawby Brook is also shown with relatively few houses evident but plenty of river meadows on Silversides near the 'New' Ancholme.
Next time you visit the Black Bull for a drink, pop in and take a good look at this map.