Samsara.

Three Characteristics of Samsara 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 …

…We are not suffering because everything is impermanent but because we believe things are permanent. Furthermore whatever is impermanent and is suffering is without a permanent self. Until we figure out that nothing is permanent and nothing has a self we will be suffering. When we do finally figure out the truth of all three characteristics of Samara we will finally see the light and be alleviated from the cycle of Samsara and attain Nirvana.