World War 1
Worldwar1.com: Trenches on the Web: The Trenches at Messines 1916 17
Shows British maps of trench warfare and gives a brief explanation.
World War 1
Worldwar1.com: Trenches on the Web: British Trench Warfare 1917 1918
Part of that excellent site "Trenches on the Web," this page gives an excerpt from "Notes for Infantry Officers on Trench Warfare." Also includes trench diagrams.
World War 1
Worldwar1.com: Trenches on the Web: Photo Archive: The Ypres Salient, 1917
Photos to click on to see images of World War I trenches: "An Australian trench," "British infantry knee deep in mud," "An abandoned German trench at Messines Ridge".