Alþingi is the national parliament of Iceland, established in 930 AD, making it one of the oldest parliaments in the world. It is located in Reykjavík and serves as the legislative body responsible for making laws, approving budgets, and overseeing the government. The parliament consists of 63 members, known as Alþingismenn, who are elected every four years. The main functions of Alþingi include debating and passing legislation, representing the interests of the public, and holding the government accountable for its actions.