Medicare is a federal health insurance program for people over 65 and certain disabled individuals. It was created in 1965 to help seniors and others access healthcare regardless of income or medical history. Medicare has 4 main parts that cover different types of care - Part A covers hospital stays, Part B covers medical services, Part C provides Medicare Advantage plans, and Part D covers prescription drugs. However, rising healthcare costs and a decreasing ratio of taxpayers to beneficiaries threatens the program's sustainability.