The Prophet's Pledge to Mecca

A group of 73 people come to the Prophet SalaAllahu Alaihi Wasallam and take this pledge with him. They have to secretly plan this meeting because if Mecca finds out, that's going to be a problem. So they wait for the middle of Tashriq after the 11th day of Hajj and they meet in this place right behind the Jamerats. Within a year, every single household in that city had learned the religion and believed in the prophet.