President Truman announced to the people of America that they successfully developed a hydrogen bomb.
Source
The first telephone call was made across the Atlantic – from London to New York.
Italy used its current tri-colored flag for the first time.
The first-ever photograph of genes was taken.
The iconic Leaning Tower of Pisa leaned 'too far,' which resulted in its closure.
A 57-year-old man received the first transplanted heart from a genetically modified pig.
