Good morning, everyone. Today we're going to discuss the history of the postal service. Before the 19th century, sending a letter was very expensive, and the cost was usually paid by the recipient, not the sender. This changed in 1840 when the first postage stamp, the Penny Black, was introduced in Britain. It made postage affordable for ordinary people, and the sender paid the cost. Interestingly, the invention of the railway greatly improved the speed of mail delivery, but the most significant change came with the introduction of airmail in the early 20th century, which reduced delivery times from weeks to days.