After seizing the peninsula and holding an internationally unrecognised referendum, Russia annexes Ukraine's Crimea.
CERN announces that the ATLAS and CMS experiments at the Large Hadron Collider have observed a particle consistent with the Higgs boson.
Voters in the United Kingdom choose, by about 52 per cent, to leave the European Union.
A brief war between Russia and Georgia over South Ossetia and Abkhazia; Russia afterwards recognises both regions as independent states.
The United Kingdom becomes the first country to leave the European Union, after 47 years of membership.
The United Kingdom gives the first doses of the fully authorised Pfizer–BioNTech COVID-19 vaccine, beginning a global vaccination campaign.
Russia launches a full-scale military invasion of Ukraine, starting the largest war in Europe since the Second World War and displacing millions of people.