Ukraine

Europe's largest country by area, Ukraine has been at war with Russia since 2014 (Crimea annexation) and full-scale invasion since February 2022. Its resistance transformed European security calculations and triggered the fastest NATO expansion since the Cold War.

Ukraine declared independence from the Soviet Union in 1991. A 2014 pro-EU revolution (Euromaidan) ousted the Russia-aligned president Yanukovych, prompting Russia's annexation of Crimea and support for separatists in Donbas. The February 2022 full-scale invasion mobilised unprecedented Western military and financial support. By 2025, over 10 million Ukrainians had been internally displaced or fled abroad.