Portugal–Spain border disputed between the two countries for two hundred years. A microstate existed previously on the border called Couto Misto. Districts on the Portuguese side of the border from North to South: Provinces on the Spanish side of the border from North to South: Portugal and Spain signed the Schengen Agreement in June 1991 which came into effect on 26 March 1995, making Portugal and Spain part of the Schengen area and thus the border then became an Open border. Portugal has since reintroduced border checks several times along the border with Spain, during the UEFA Euro 2004 championships, during the
Mongolia–Russia border Mongolia–Russia border The Mongolia–Russia border (, "Mongol-Orosın xil"; , "Rossijsko-mongoljskaja granica") is the international border between the Russian Federation (CIS member) and Mongolia. It is virtually all land. The total length of the border is 3485 km. The boundary is the third longest border between Russia and another country, behind the Kazakhstan-Russia border and the China-Russia border. The Russian state expanded into the regions north of today's Mongolia in the 17th century. Much of the line of the today's Mongolia–Russia border line was set by the Treaty of Kyakhta (1727) between the Russian and Qing Empires (the Mongolia at the