The Morse code distress signal “SOS,” originating from Germany, became the world’s official message for help.
Source
The first US postage stamps were issued.
The US aired its first-ever TV commercial.
The UK returned Hong Kong's control back to China after 156 years of British rule.
Japanese whaling ships officially resumed activities after a thirty-one-year hiatus.
The Cassini–Huygens spacecraft became the first to enter Saturn's orbit.