Nirvana is a Buddhist concept of an ideal state where the spirit is liberated from the cycles of death and rebirth. Nirvana can be after life, but (Siddharta) Gautama Buddha experienced nirvana while sitting under the bodhi tree. Nirvana is called a spiritual enlightenment and release from human suffering, lust, and anger.
Source: "Nirvana" A Dictionary of Asian Mythology. David Leeming.
Oxford University Press, 2001.