What was the extent of the trench system during WW1?

Question: What was the extent of the trench system during WW1!?

any posted links to sites containing information on the extent of trench systems during WW1, would be greatly appreciated!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

See below!.Www@QuestionHome@Com

Here are two I found by doing a search for 'trench system WWI'

www!.lermuseum!.org/ler/mh/wwi/trenchsys!.!.!.
www!.schoolhistory!.co!.uk/gcselinks/wars!.!.!. Www@QuestionHome@Com