Postcards are small, printed cards designed for mailing without an envelope, often featuring a picture on one side and space for a message and address on the other. First appearing in the mid-19th century, they quickly became popular for personal communication and souvenir collecting. Picture postcards commonly depict landmarks, local scenery, cultural events, celebrities, or humorous illustrations, while real photo postcards use actual photographic prints. Postcards served not only as a means of quick communication but also as promotional tools and historical records. Today, vintage postcards are valued for their artwork, historical content, and cultural significance.