Following the Schengen Agreement, internal border checks have been abolished and replaced by effective external border control and a common visa policy. The Schengen Area is comprised of all EU member states apart from six: Bulgaria, Cyprus, Ireland, Romania and Croatia.
Iceland, Liechtenstein, Norway and Switzerland are also Schengen states, even though they do not belong to the EU. Additionally, when travelling to other EU member states which do not belong to the Schengen Area (Ireland, Bulgaria, Romania, Cyprus and Croatia), passengers need to undergo rigorous passport control at the border. The same control applies to passengers travelling to countries with temporarily reinstated border control.