The beginnings of the New York Stock Exchange are rooted in the agreement of 24 brokers who decided in 1792 to trade securities only among themselves. The pledge they signed, called the Buttonwood Agreement, was named for their meeting place under a buttonwood tree that faced 68 Wall St. The exchange is currently closed to visitors. 20 Broad St., between Wall and Exchange (subway line J or Z to Broad Street; 2, 3, 4 or 5 to Wall Street), Manhattan, New York City. Phone 212-656-3000. http://www.nyse.com.