Citizens across the European Union are currently voting in the European Parliament elections to choose direct representatives for the supranational legislative body.

The European Parliament is one of the EU's three main political institutions, along with the European Council, which represents national governments of the 27 member states, and the European Commission, the bloc's Brussels-based executive arm.

The European Commission can formally propose new laws, which are passed through an agreement between the European Parliament and the Council of the European Union, composed of national government ministers of a particular policy area.

Both institutions can reject a law at any stage of the process.

Member states hold a de facto veto power in areas requiring unanimity.

EU countries' heads of state or government meet in the European Council to resolve issues, set priorities, and address global matters.

They also propose the President of the European Commission, who needs majority backing in the Parliament.

The European Council appoints the European Commission and other key officials.

The EU budget is contributed to and received by countries based on their economy, adherence to EU law, and policy needs.

Treaties, regulations, and directives form the core of EU law, interpreted by the Court of Justice of the EU, which can impose fines for breaches.