Nagorno-Karabakh is a region in the South Caucasus. It is recognized by other countries as part of Azerbaijan, but from 1994 until the 2020 Nagorno-Karabakh war, most of it was militarily controlled by Armenians as the Republic of Artsakh, which was not officially recognized by any other country, including Armenia which supported it.
In September of 2023, Azerbaijan invaded the Artsakh Republic after a long siege. Within a few days, Artsakh surrendered and came under the control of Azerbaijan. Nearly all of Artsakh's population fled to Armenia as refugees.