Vast central plain mountains in west hills and low mountains in east; rugged mountains and broad river valleys in Alaska; rugged volcanic topography in Hawaii
Climate
Mostly temperate but tropical in Hawaii and Florida arctic in Alaska semiarid in the great plains west of the Mississippi River and arid in the Great Basin of the southwest; low winter temperatures in the northwest are ameliorated occasionally in January and February by warm chinook winds from the eastern slopes of the Rocky Mountains
Natural Hazards
Vast central plain mountains in west hills and low mountains in east; rugged mountains and broad river valleys in Alaska; rugged volcanic topography in Hawaii
Note:
World's third-largest country by size (after Russia and Canada) and by population (after China and India); Mt. McKinley is highest point in North America and Death Valley the lowest point on the continent
Britain's American colonies broke with the mother country in 1776 and were recognized as the new nation of the United States of America following the Treaty of Paris in 1783. During the 19th and 20th centuries 37 new states were added to the original 13 as the nation expanded across the North American continent and acquired a number of overseas possessions. The two most traumatic experiences in the nation's history were the Civil War (1861-65) in which a northern Union of states defeated a secessionist Confederacy of 11 southern slave states and the Great Depression of the 1930s an economic downturn during which about a quarter of the labor force lost its jobs. Buoyed by victories in World Wars I and II and the end of the Cold War in 1991 the US remains the world's most powerful nation state. The economy is marked by steady growth low unemployment and inflation and rapid advances in technology. Read more on Wikipedia
