A thangka is a painted or embroidered Buddhist banner which is hung in a monastery or a family altar and occasionally carried by monks in ceremonial processions. Sometimes a thangka is called a scroll painting. Originally, thangka painting became popular among traveling monks because the scroll paintings were easily rolled and transported from monastery to monastery. These thangka served as important teaching tools depicting the life of the Buddha, various influential lamas and other deities and bodhisattvas. One popular subject is The Wheel of Life.