1917

Just caught it yesterday. Good movie, not really great. Some really wicked scenes.

Another point on trench warfare - while it was used all over the Western front, it was not used on the Eastern front much. So it was also the circumstances that dictated the use of trenches.

Also, trenches were used in WW2 and even today. But it was nowhere near the extensive, almost static trench network of WW1. By WW2 the focus had switched to developing strongpoints held by smaller units, at the level of roughly a battalion, that could not be flanked and were not linked. Also still their were permanent fortifications such as the Maginot line and the Atlantikwall, and the Siegfried lne. All of which accomplished only delaying an eventual defeat. More forward thinking generals like von Manstein understood this, and the idea was to always be on the move, and looking towards the next offensive, and not be stuck in a static situation for long.