What reasons led to the outbreak of the First World War?

The First World War became one of the largest wars in the history of the 20th century. The reason for its denouement was the accumulated tension between the advanced states. A characteristic feature of this war was that it was imperialist, since the countries of the first echelon sought to maintain world domination and colonies, and the countries of the second echelon of development, on the contrary, sought to divide the world into new spheres of influence. The conflict was complicated by local grievances and small strikes between people from different countries.