Same-sex marriage became legal in Austria.
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Ellis Island opened as a US immigration inspection station.
The dwarf planet Ceres was discovered by an Italian monk called Giuseppe Piazzi.
The Union Jack flag was flown for the first time in Dublin, Ireland, to commemorate the union between Great Britain and Ireland.
Medical researcher Oswald Hope Robertson performed the first-ever blood transfusion using stored and refrigerated blood.
Portuguese navigators discovered Rio de Janeiro.
