In the 30's of the twentieth century, Western Union has become the world's largest telegraph company. In 1877, starting from September, New York City residents began to have the opportunity to check the time on clock with the "time ball", located on the roof of constructed in the same year a new corporate headquarters - Western Union Building. In 1914 Western Union engineers invented the first payment card - a prototype of the modern credit card. In 1884 Western Union has become a joint-stock company and was brought to the stock exchange. The company has entered in the first American stock index Dow Jones.