The Chinese started using carrier pigeons to deliver mail from 1000 BC. But the first large-scale use of pigeons to deliver mail in modern times occurred in Paris during the 1870s.
When France and Prussia were at war, and the Prussians had surrounded the city of Paris. For many months the Parisians could do nothing, including delivering mail, or entering or leaving the city.
But the French found an ingenious way to make the postal system work. Mail was sent to compatriots outside Paris by hot air balloons, as well as by hundreds of carrier pigeons.
The letters that were sent to Paris were first converted into photographs, therefore it was the films or negatives inside small jars, approximately 30,000 of them, that were sent.
These jars were tied to the pigeons, and the pigeons went to Paris. Thirty-five pigeons carried the same letters, so that if any were injured by the enemy, at least one would reach Paris.
In Paris, the film was projected on a screen, and the letters were copied by hand to be delivered to the homes of the city.
.
