An invasion is a military offensive of combatants of one geopolitical entity, usually in large numbers, entering territory controlled by another similar entity. Generally, invasions have objectives of conquering, liberating or reestablishing control or authority over a territory; forcing the partition of a country; altering the established government or gaining concessions from said government; or a combination thereof. An invasion can be the cause of a war, be a part of a larger strategy to end a war, or it can constitute an entire war in itself. Due to the large scale of the operations associated with invasions, they are usually strategic in planning and execution. Not every military offense with the goal to capture territory or remove a government is an invasion.
During the U.S Invasion of Grenada, an American Sikorsky CH-53 Sea Stallion helicopter hovers over an abandoned Soviet ZU-23-2 anti-aircraft weapon.
A defensive wall, the Great Wall of China.
View from Dover Castle.
The view from a battery at Ouvrage Schoenenbourg in Alsace; notice the retractable turret in the left foreground.
A military, also known collectively as an armed forces, are a heavily armed, highly organized force primarily intended for warfare. Militaries are typically authorized and maintained by a sovereign state, with their members identifiable by a distinct military uniform. They may consist of one or more military branches such as an army, navy, air force, space force, marines, or coast guard. The main task of a military is usually defined as defence of their state and its interests against external armed threats.
NATO military ceremony in Pabrade, Lithuania, November 2014
Relief scene of Roman legionaries marching, from the Column of Marcus Aurelius, Rome, Italy, 2nd century AD
Depiction of ancient Egyptian military formation
Finnish and American soldiers training together in arctic conditions in Lapland, Finland, January 6–16, 2015
