Discover published sets by community

Ancient Times to 19th Century; used by Native Americans and in ancient China for sending signals over long distances.

Ancient times; used to send messages through loud and rhythmic beats across distances in Africa and the Americas.

Ancient Times to 20th Century; individuals who physically carried messages from one location to another.

19th Century to present; a type of pyrotechnic that produces a brilliant light or intense heat without an explosion.

Late 18th Century to 19th Century; a system of conveying information by means of visual signals, using towers with pivoting blades or paddles.

Ancient Times to present; silent and visual signals used by soldiers to communicate without making noise.

Late 19th Century to 20th Century; used a mirror to reflect sunlight to send morse code messages.

17th Century to present; naval communication method using flags to represent letters or numbers typically to convey tactical messages.

20th Century to present; a mirror used to send simple messages by reflecting sunlight.

18th Century to 20th Century; brass instruments used to signal various military activities, from wake-up calls to charges.

Late 19th Century to mid-20th Century; a signaling device that uses a light source to transmit Morse code messages.

19th Century to mid-20th Century; messengers who carried written orders or reports on horseback or motorcycles.

Ancient Times to 20th Century; birds used to send messages over long distances by delivering small paper messages.

20th Century to present; a wireless communication method that uses radio waves to transmit information.