One of the things that AMEX is famous for, is the introduction of the wild hand signals that the general public recognize in stock brokers. This came about during its time as the New York Curb Exchange, when the brokers used to trade outdoors. When the weather was particularly bad, brokers had to shout to make themselves audible above the winds. Since this was often more difficult than not, hand signals were invented, and they're still used to this day, even inside the larger stock exchange buildings and floors of Wall Street.
American stock exchange now known as NYSE American actually merged with one of its biggest rivals, NASDAQ, back in 1998, although the merger was short-lived, more due to the petty feuds between the two different sets of brokers. Following one too many disagreements, AMEX actually bought the NASD and has been a separate entity since 2004.