Slovakia
The Slovak Republic and the Czech Republic went their separate ways after 1 January 1993, an event sometimes called the Velvet Divorce. Slovakia has remained a close partner with the Czech Republic. Both countries co-operate with Hungary and Poland in the Visegrád Group. Slovakia became a member of NATO on 29 March 2004 and of the European Union on 1 May 2004. On 1 January 2009, Slovakia adopted the Euro as its national currency.
Poland–Slovakia border
When the Republic of Slovakia was established on March 14, 1939 (officially independent, but controlled by Nazi Germany), the Polish-Czechoslovak border ceased to exist, which became part of the Polish-Czech border (with the Protectorate of Bohemia and Moravia), the Polish border. Slovak and Polish-Hungarian border.