The Battle of Vimy Ridge was the first time all four divisions of the Canadian Expeditionary Force participated in a battle as a cohesive formation, and it became a Canadian national symbol of achievement and sacrifice. France ceded to Canada perpetual use of a portion of land on Vimy Ridge on the understanding that Canada use the land to establish a battlefield park and memorial. Wartime tunnels, trenches, craters, and unexploded munitions still honeycomb the grounds of the site, which remains largely closed off for reasons of public safety. Along with preserved trench lines, several other memorials and cemeteries are contained within the park.