The telegraph was, arguably, one of the two most important technological advances that contributed to U.S. settlement of North America west of the Mississippi River. (The other was the railroad.) The telegraph is still occasionally used for communication, but the Internet and the telephone are employed far more often. A variant of the original Morse code is used by amateur radio operators today, largely for recreation, but occasionally in emergencies when all other modes of communication fail as a result of infrastructure damage or because of poor wave propagation conditions.