On September 12, 1776, Nathan Hale left Harlem Heights Camp (127th St) for his spy mission. From the article:
"Nathan Hale was an American soldier during the Revolutionary War and was hanged by the British for espionage in 1776.
Who Was Nathan Hale?
After graduating from Yale University, Nathan Hale became a schoolteacher. When war began in the American colonies, he joined a Connecticut regiment and was made a captain in 1776. On a secret mission ordered by General George Washington, Hale went behind enemy lines to gather information on the British army’s location. He was captured by the British in New York City and hanged for espionage on September 22, 1776."