During WW1 the front moved rapidly from west of Ukraine's western end to east of its eastern. There's a fine map at the top of https://www.britannica.com/event/

During WW1 the front moved rapidly from west of Ukraine's western end to east of its eastern. There's a fine map at the top of https://www.britannica.com/event/Eastern-Front-World-War-I-history https://www.britannica.com/event/Eastern-Front-World-War-I-h... That trench warfare was a feature of one front of the war, a rather special case. It wasn't even unique to WW1.