May 20, 2010 (Thursday)
- Floods in Poland kill 5. The downpours also cause flooding in areas of Hungary, Slovakia and the Czech Republic. (cntv)
- At least one police officer is killed and five other people are injured in a battle with a dissident army unit in Antananarivo. (Al Jazeera)
- Numerous countries condemn North Korea for the sinking of the South Korean vessel Cheonan; North Korea denies involvement, and threatens war if sanctions are imposed. (BBC)
- Malawi, considering them to be a gay couple, sentences a transgender woman and a cisgender man to 14 years of hard labour. (The New York Times) (BBC)
- Scientists at the J. Craig Venter Institute announce the successful transplant of a synthesized genome into an existing cell, creating the world's first artificial lifeform (Mycoplasma laboratorium). (The Guardian) (Economist) (BBC) (Financial Times)