Nigerian Civil War: Nigerian forces invade Biafra, beginning the war.

The Nigerian Civil War, also known as the Biafran War, Nigeria-Biafra War, or Biafra War, was an armed conflict fought between Nigeria and the Republic of Biafra, a secessionist state that had declared its independence from Nigeria in 1967. During the war years, Field Marshal Gowon served as the head of state of Nigeria, while Biafra was led by Lieutenant Colonel Chukwuemeka "Emeka" Odumegwu Ojukwu. The conflict emerged from political, ethnic, cultural, and religious tensions that preceded the United Kingdom's formal decolonisation of Nigeria from 1960 to 1963. Immediate causes of the war in 1966 included a military coup, a counter-coup, and anti-Igbo pogroms in the Northern Region. As a consequence of these pogroms, alongside the mass exodus of surviving Igbos from the Northern Region to the Igbo homelands in the Eastern Region, the leadership of the Eastern Region concluded that the Nigerian federal government was either unwilling or unable to guarantee them an adequate protection, therefore, the only remaining solution seemed to be to secure their compatriots' security by establishing a sovereign and independent country of Biafra.