Ukraine (incorrectly often called the Ukraine) is a country in the crossroads between central Europe and eastern Europe with the capital in Kiev. Ukraine used to be part of the USSR but got independence when the Soviet Union broke up. In 2012, Ukraine hosted with Poland the EURO 2012. It is a country of strategic importance to the EU and it hopes to join the European Union by 2020.
Ukraine was a medieval polity in Europe, from the late 9th to the mid 13th century, when it disintegrated under the pressure of the Mongol invasion of 1237–1240. It was conquered and divided by its neighbouring countries.
Ukrainian SSR, a republic within the USSR
Ukrainian SSR was commonly called Ukraine or Soviet Ukraine. It was a sovereign Soviet socialist state and one of the fifteen constituent republics of the Soviet Union from its inception in 1922 to its breakup in 1991. Ukrainian SSR was the place where the disastrous Chernobyl disaster happened.
The Great Hunger, Genocide under Stalin
The USSR under Stalin caused a devastating and unnecessary famine that affected especially Ukraine. Food was available but on Stalin’s orders hungry people were prevented from getting to it. There are estimates that between 7 million and 11 million people died. The exact reasons why Stalin did this are unclear but Ukrainians historically had a strong wish for independence from Russia and resisted Stalinist rule determinedly, also it seems Stalin had a personal dislike of Ukraine and its leaders.  
The Chernobyl Nuclear Power Plant is in Ukraine. The explosion there caused a major environmental disaster. It became a symbol of communism's lack of care about the natural environment, in the endless strife for progress.
The Act of Declaration of Independence of Ukraine (Ukrainian: Акт проголошення незалежності України, or Akt proholoshennya nezalezhnosti Ukrayini) was adopted by the Ukrainian parliament on 24 August 1991. The Act established Ukraine as an independent, democratic state.
Ukraine is the second largest European country after (European part of) Russia, and 7th European country by population. Russia has at times tried to dominate Ukraine, putting it in Russian sphere of inference, including threats to cut off gas supply during cold Ukrainian winter.
In 2013, after its president Yanukovych declined to sign, peaceful protests begun. The presidential response was to stop it by force, which caused even mere intense protests, leading to his deposition and a formation of a new government, as well as early presidential elections in May 2014 and early parliamentary elections in October 2014. Abusing the difficult situation, Russia started sending military units without badges to Crimea and Donbass.