Ridderronde Maastricht is held in the country that  borders what country on the east?
Netherlands The Netherlands ( ; Dutch: "Nederland" ] ; West Frisian: "Nederlân" ), also known informally as Holland, is a densely populated country in Western Europe, also incorporating three island territories in the Caribbean. It is the main constituent country of the Kingdom of the Netherlands. The European portion of the Netherlands borders Germany to the east, Belgium to the south, and the North Sea to the northwest, sharing maritime borders in the North Sea with Belgium, the United Kingdom, and Germany. The four largest cities in the Netherlands are Amsterdam, Rotterdam, The Hague and Utrecht. Amsterdam is the country's capital, while The Hague holds the Dutch seat of parliament and government. The port of Rotterdam is the largest port in Europe and the world's largest outside east Asia. Utrecht is a central node for road and railway communications, commerce, and cultural events.
Oder–Neisse line The Oder–Neisse line (Polish: "granica na Odrze i Nysie Łużyckiej" , German: "Oder-Neiße-Grenze" ) is the international border between Germany and Poland. It was drawn at the Potsdam Conference in the aftermath of the Second World War and is primarily delineated along the Oder and Lusatian Neisse rivers in Central Europe, meeting the Baltic Sea to the north, just west of the Polish seaports of Szczecin and Świnoujście (German: "Stettin" and "Swinemünde"). All prewar German territory east of the line and within the 1937 German boundaries (23.8% of the former Weimar Republic) were placed under International Law Administrative status, with most of it being made part of newly-Communist Poland. The small remainder, consisting of the territory surrounding the German city of Königsberg (now renamed Kaliningrad, in honour of Soviet head of state Mikhail Kalinin) in northern East Prussia, was allocated to the Soviet Union (as Kaliningrad Oblast of the Russian SFSR, today the Russian Federation) after the war (pending the final World War II peace treaty for Germany). The vast majority of the native German population in these territories fled, or were killed or expelled by force. The Oder–Neisse line marked the border between the German Democratic Republic (East Germany) and Poland from 1950 to 1990. East Germany confirmed the border with Poland in 1950, while West Germany, after a period of refusal, finally accepted the border (with reservations) in 1970. In 1990 the newly reunified Germany and the Republic of Poland signed a treaty recognizing it as their border.