During the Tatmadaw's (Myanmar Armed Forces') heavy militarisation of the state in the late 1940s and early 1950s, locals accused them of mistreating, torturing, robbing, raping, unlawfully arresting and massacring villagers. As a result, on 21 May 1958, an armed resistance movement, led by Sao Noi and Saw Yanna, was started in Shan State.
On 20 May 1977, the leader of the only recently legalized Spanish Socialist Workers' Party (PSOE), Felipe González, accompanied by Javier Solana, visited Juan Carlos in the Zarzuela Palace. The event represented a key endorsement of the monarchy from Spain's political left, who had been historically republican. Left-wing support for the monarchy grew when the Communist Party of Spain was legalized shortly thereafter, a move Juan Carlos had pressed for, despite enormous right-wing military opposition at that time, during the Cold War.
On 20 May 1982, Robert Muldoon announced that New Zealand would make HMNZS Canterbury, a Leander-class frigate, available for use where the British thought fit to release a Royal Navy vessel for the Falklands. The New Zealand government expelled the Argentinian ambassador following the invasion. The Prime Minister, Robert Muldoon, was in London when the war broke out.
The Chinese government declared martial law on 20 May and mobilized at least 30 divisions from five of the country's seven military regions. At least 14 of PLA's 24 army corps contributed troops. As many as 250,000 troops were eventually sent to the capital, some arriving by air and others by rail.
At the 1989 FA Cup Final between Liverpool and local rivals Everton, held just five weeks after the Hillsborough disaster, the players from both participating teams wore black armbands as a gesture of respect to the victims.
The 1992 European Cup Final was a football match held on 20 May 1992 at Wembley Stadium, London, between Sampdoria of Italy and Barcelona of Spain. Barcelona won the game 1–0 after extra time, thanks to a Ronald Koeman free kick, to record their first triumph in the competition. It was the first to have a group stage involving the eight second-round winners split into two groups, and the winner of each one met in the final. In doing so, they became the second Spanish club to win the tournament and the 19th overall.
On May 20, 2010, Tesla and Toyota announced a partnership to work on electric vehicle development, which included Toyota's US$50 million future conditional investment in Tesla and Tesla's US$42 million purchase of a portion of the former NUMMI factory.