May 21, 2017 (Sunday)
Armed conflicts and attacks
- War in Afghanistan (2001–2021)
- A Taliban raid kills at least 20 Afghan police officers in southern Afghanistan. (AFP via Dunya News)
- An Indonesian maritime patrol boat, the KM Hiu Macan 001, intercepts five boats and arrested 55 Vietnamese crew members for allegedly poaching off Natuna Islands, but after an unexpected aggressive intervention by Vietnamese coast guards forces the Indonesian authorities to back off, release the arrested men and return to base empty handed. (The Star)
Arts and culture
- After 146 years, the Ringling Bros. and Barnum & Bailey Circus comes to a close. (The New York Times)
- In a surprise appointment by Pope Francis, Bishop Anders Arborelius is the first ever person from Sweden to become a cardinal. (CNS)
Disasters and accidents
- Mountaineers led by Tim Mosedale confirm suspicions that Mount Everest's famous Hillary Step had completely collapsed. (BBC)
International relations
- North Korea and weapons of mass destruction
- South Korea reports North Korea fired a Pukguksong-2 intermediate-range ballistic missile that flew 500 km before landing in the Sea of Japan. [http://www.abc.net.au/news/2017-05-21/north-korea-unidentified-projectile-south-military-says/8545408 (Reuters