Continuing and concluding.
Your military geography lesson further all thanks once more to Robert Cowley and his article from "Military History".
1. Oceans.
"the greatest part of the earth's surface has been hardly, if at all, touched by war. Most of History's major naval battles, for instance, have been fought inshore, often as an adjunct to land campaigns. Opposing naval forces have trouble finding one another in the open ocean . . . even as late as World War II."
ON THE WATER AND BELOW THE WATER BOTH IN THE MODERN CONTEXT.
Just in number of participants the largest naval battle of all-time fought entirely inland, brown-water naval combat.
2. Seventy percent [70 %].
"'Almost seventy per cent of the world's 60 million square miles [about 160 million square kilometers] of dry land' . . . 'is either too high, too cold, or too waterless for the conduct of military activities.'" - - Sir John Keegan.
With exception consider [and then only on a limited basis] areas such as desert, jungle, woodland historically not places where large-scale combat fought.
Woodland where the predominant growth of trees is eighteen inches or greater [about forty-six centimeters] in diameter normally not passable by an armored force.
URBAN TERRAIN AND URBAN WARFARE IN ADDITION GENERALLY PRESENTING A SERIES OF DIFFICULTIES UNIQUE AND HAZARDOUS IN THE EXTREME FOR THE ATTACKING FORCE. URBAN WARFARE TO BE AVOIDED IN ALL POSSIBLE CIRCUMSTANCES.
coolbert.