Euthanasia is the practice of intentionally ending a person's life to relieve them from suffering, often due to terminal illness or severe pain. It can be voluntary, where the person requests it, or involuntary, where it is done without their explicit consent. The process can involve administering lethal substances or withholding life-sustaining treatments. There are different types of euthanasia, including active euthanasia, where direct action is taken to cause death, and passive euthanasia, which involves allowing a person to die by not intervening in their medical care. The legality and ethical considerations surrounding euthanasia vary widely across different countries and cultures.