European citizenship was introduced by the 1992 Maastricht Treaty and provides citizens of EU countries with rights such as voting in European elections, free movement within the EU, and consular protection from other EU states when traveling. It is supplementary to national citizenship. Key rights include free movement and residence within the EU, protection from discrimination based on nationality, voting rights, access to EU documents, and consular protection abroad. European citizenship does not replace national citizenship and is acquired based on the rules of one's EU member state nationality.