The first Buddhist monks did not build monasteries. Instead, they were homeless mendicants who begged for all their food. Their only possessions were their robe and begging bowl.
Today, in many predominately Theravada countries like Thailand, monks still rely on receiving alms for most of their food. The monks leave the monasteries early in the morning. They walk single file, oldest first, carrying their alms bowls in front of them. Laypeople wait for them, sometimes kneeling, and place food, flowers or incense sticks in the bowls. Women must be careful not to touch the monks.