Italy used its current tri-colored flag for the first time.
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A 57-year-old man received the first transplanted heart from a genetically modified pig.
The first-ever photograph of genes was taken.
The US celebrated the opening of the country's first railroad station in Baltimore.
President Truman announced to the people of America that they successfully developed a hydrogen bomb.
The first telephone call was made across the Atlantic – from London to New York.
