Turkmenistan declared independence from the Soviet Union.
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Inventor Fred Waller patented the aquaplane, which would become water skis.
Roman Emperor Constantine had his Vision of the Cross.
The first successful operation of conjoined twins joined at the head was completed in New Delhi, India.
Englishman William Penn founded Philadelphia, Pennsylvania.
Gliese 229B became the first brown dwarf to be seen and identified by astronomers.
