Wide shell craters just short of the enemy trenches, unprotected but close enough to enjoin tunnels from.
A ring of wide craters sits immediately in front of the enemy trench line, blasted out by the earlier bombardment. When Colonel Boomer calls "Hitting the craters" and Carl approves, the ground gives way under him and his squad drops in: Mongo lands deftly, Imani lands to his left with two casualties over her shoulders, and the rest of the squad scatters into neighboring craters.
They offer no real protection — Carl knows grenades will be raining down on them at any moment — but they are close enough to the enemy line for the Build Trench Exploit. Carl switches the Warlord Chat to Near Proximity Band, reads his Build Trench Scroll, and cuts a channel that enjoins the enemy trench in a T. All along the line, soldiers in other craters do the same, opening dozens of breaches at once.
Wide, open shell craters in torn battlefield dirt, lower in elevation than the enemy trenches they sit before, littered with rocks and bodies.
The jumping-off positions from which the crawlers punch their trench breaches.