Plat maps, land use maps, survey maps…etc can date to the early 1900’s and late 1800’s. Preserved & converted to digital form for country-side USGIS visualizations and mapping.
Or architectural blueprints, or sewer/water line diagrams/maps. Electrical & communication lines are approaching that age. Transportation infrastructure and diagrams.
We reference documents & technical knowledge that’s 30-50 years old, sometimes 70-80 years old right now in our industry. Mathematics knowledge that’s well over 100 years old.
There are countless examples of important things that are as old as the industry itself.
It’s essentially guaranteed that we will be referencing technical documentation and design and knowledge that is over 100 years old once this industry is old enough.