The crisis in Ukraine started on November 21, 2013. The Ukraine government was about to sign and agreement with the European Union, which will allow them to be a part of the EU trading block. Unfortunately, the president of Ukraine at that time Viktor Yanukovych eliminated all preparations, and the association agreement could not longer be implemented.
There were massive protests from the supporters of the agreement and eventually, a revolution was initiated by the organizers of the protests, resulting in Mr. Yanukovych destitution from power. After his ousting from power the eastern and Southern regions of Ukraine began to unrest because they were loyal supporters of Yanukovych, and they were not very happy about the situation.
The situation turned into a full blown political crisis when Russia, aware of what was happening invaded them regions, and took control and later annexed the Ukrainian region of Crimea which was an autonomous area at the time. Later the protesters against the revolutionary government of Ukraine became a pro-Russian insurgency, often equipped and trained by Russian forces. The conflict is still going on and has the potential to turn at any time into a full blown war.