Samsara by definition is the eternal cycle of birth, suffering, death, and rebirth. During the Buddha's last lifetime he came to the understanding that Samsara has three characteristics that even the heavens abide by: impermanence, suffering, and no-self. It is these three characteristics that keep us trapped in the cycle of Samsara and until we come to realize the truth about each of them we will never gain Nirvana.
The first of the three characteristics is impermanence. According to the Buddha nothing in the universe is permanent, everything is constantly changing. In Sangitiyavamsa's view of the Buddha's life we see his first experience of impermanence. While in his garden where he was planning to go play he saw an old person. This was surprising to him because all of his life he was raised in a very sheltered surrounding; a life where he was prevented from witnessing old age. …