The Schengen Agreement led to the creation of Europe’s borderless Schengen Area. The treaty was signed on 14 June 1985 by five of the ten member states of the European Economic Community near the town of Schengen in Luxembourg but was not implemented (partially) until 1995. It proposed the gradual abolition of border checks at the signatories’ common borders. Measures proposed included reduced speed vehicle checks which allowed vehicles to cross borders without stopping, allowing of residents in border areas freedom to cross borders away from fixed checkpoints and the harmonisation of visa policies.
In 1990 the Agreement was supplemented by the Schengen Convention which proposed the abolition of internal border controls and a common visa policy. The Schengen Area operates very much like a single state for international travel purposes with external border controls for travellers entering and exiting the area, and common visas, but with no internal border controls. It currently consists of 26 European countries covering a population of over 400 million people and an area of 4,312,099 square kilometres (1,664,911 sq mi).
Prior to 1999, the Schengen treaties and the rules adopted under them operated independently from the European Union; however, the Amsterdam Treaty incorporated them into European Union law, while providing opt-outs for the only two EU member states which had remained outside the Area: Ireland and the United Kingdom. Schengen is now a core part of EU law and all EU member states without an opt-out which have not already joined the Schengen Area are legally obliged to do so when technical requirements have been met. Several non-EU countries are also included in the area.