Umuahia is the capital of Abia State and a busy Igbo market city in southeastern Nigeria. For most travellers it is not a casual sightseeing town. Its pull is specific and serious: it was the second capital of Biafra during the Nigerian Civil War, and two of the country's most important Civil War memory sites are here.
The National War Museum is the main reason to come. Its galleries and outdoor military hardware cover Nigerian military history and the 1967-1970 war, while the site is tied to wartime Voice of Biafra radio transmissions. The separate Ojukwu's Bunker is the underground command post associated with Biafran leader Chukwuemeka Odumegwu Ojukwu.
That is enough to clear the destination bar, but only for travellers who want difficult history. Check current security and transport advice before making plans, use local guidance, and do not treat the museum sites as casual photo stops.