Colors on a physical map might never used to show an areas , or height above sea level

im pretty sure it has something to do with the end of ww1

although world war i began in 1914, the united states did not join the war until 1917. the additional firepower, resources, and soldiers of the u.s. to tip the balance of the war in favor of the allies. remaining neutral. when war broke out in 1914, the united states had a policy of neutrality.