Blitzkrieg (‘lightning war’ in German; listen (help·info)) is a popular name for an offensive operational-level military octrine which involves an initial bombardment followed by the employment of motorized mobile forces attacking with speed and surprise to prevent an enemy from implementing a coherent defense. The founding principles of these types of operations were developed in the 20th century by various nations, and adapted in the years after World War I, largely by the German Wehrmacht, to incorporate modern weapons and vehicles as a method to help avoid the stalemate of trench warfare and linear warfare in future conflicts. The first practical implementations of these concepts coupled with modern technology were instituted by the Wehrmacht in the opening theatres of World War II.