War film is a film genre concerned with warfare, typically about naval, air, or land battles, with combat scenes central to the drama. It has been strongly associated with the 20th century. The fateful nature of battle scenes means that war films often end with them. Themes explored include combat, survival and escape, camaraderie between soldiers, sacrifice, the futility and inhumanity of battle, the effects of war on society, and the moral and human issues raised by war. War films are often categorized by their milieu, such as the Korean War; the most popular subject is the Second World War. The stories told may be fiction, historical drama, or biographical. Critics have noted similarities between the Western and the war film.