Military decision makers have been considering terrain in their military action plans for thousands of years. By terrain herein is the very broad, detailed, local, and real-time consideration of: water, oil and gas, rock, mineral, forest and other resources; land suitable for tunnels, trenches, and rock walls; topography and landforms in the interest of mobility and ground control; access to safe and protective shelter, stable transportation routes; and other issues. It’s clear to the everyday observe that: water is vital; excavatable rocks are easier for tunneling, diggable soils are suitable for trenching, and large rocks are suitable for wall- making than otherwise; flat open or valley lands are easier to conquer than hills or rugged mountains; high ground capture can control surrounding low ground; sand dunes and mud are more difficult to travel over than hard ground; safety behind high, leafy, and dense vegetation is more secure than an open meadow; and seasons and weather may make terrain conditions more or less favorable.