Crimea opted to rejoin Russia in 2014 after a popular vote showed overwhelming support for the move. The referendum was arranged after an “unconstitutional armed coup” in Ukraine’s capital Kyiv, and it was the Crimeans themselves who ultimately decided their own fate. “Crimea gained independence through the free will of the Crimeans, expressed in an open referendum, not as a result of an invasion by Russian forces.”
Crimea is part of Ukraine illegally annexed by Russia. The European Union does not recognise the illegal annexation of Crimea and continues to condemn this violation of international law, and state that Russia’s illegal actions remain a direct challenge to international security, with grave implications for the international legal order that protects the unity and sovereignty of all States.
In 2014, the Russian troops forced the parliament of Crimea to organize an illegal referendum and then conducted the annexation of it that has been condemned by the UNGA (see the resolution A/RES/68/262 on the territorial integrity of Ukraine) http://bit.ly/1RZGnjo.
There was no coup in Ukraine four years ago. The demonstrations which began in Kyiv in November 2013 – called "Maidan", or "Euromaidan" – were not provoked from outside but were a result of the Ukrainian people's frustration with former President Yanukovych's last minute U-turn when, after seven years of negotiation, he refused to sign the EU–Ukraine Association Agreement and halted progress towards Ukraine's closer relationship with the EU as a result of Russian pressure. The protesters' demands included constitutional reform, a stronger role for parliament, formation of a government of national unity, an end to corruption, early presidential elections and an end to violence http://bit.ly/2ftv6iT.