The North East's coal mining past is an important part of our heritage, but how much do you know about its effect on the area where you live?
At the industry's peak, there were 400 pits, employing a quarter of a million people.
The records of the Durham Miners' Association from that time are held at Sunderland University.
Now for the first time, the whole collection is available on the internet. It is attracting interest from scholars all over the world. Lucy Taylor has been to see it.
More top news
Veterans, cadets, dignitaries and serving Northumberland Fusiliers have paid tribute to those killed at the Battle of the Somme
Clear spells. Showers. Brisk winds. Sunday looks like the better day
Two men whose grandfathers fought in the Tyneside Irish battalion and died together on the Somme have returned to visit their graves.