Luxembourg served on the United Nations Security Council for the years 20, which was a first in the country's history.
In 2016 Luxembourgish citizens had visa-free or visa-on-arrival access to 172 countries and territories, ranking the Luxembourgian passport equal 15th in the world, tied with countries such as Canada and Switzerland.
In the following centuries, Luxembourg's fortress was steadily enlarged and strengthened by its successive occupants, the Bourbons, Habsburgs, Hohenzollerns and the French.
With an area of 2,586 square kilometres (998 sq mi), it is one of the smallest sovereign states in Europe, about the same size as the US state of Rhode Island or the English county of Northamptonshire.After the decline of the steel industry in the 1970s, the country focused on establishing itself as a global financial centre and developed into the banking hub it is reputed for.Since the beginning of the 21st century, its governments have focused on developing the country into a knowledge economy, with the founding of the University of Luxembourg and a national space programme, projecting the first involvement in a robotic lunar expedition by 2020.In the 14th and early 15th centuries, three members of the House of Luxembourg reigned as Holy Roman Emperors.
In 1437, the House of Luxembourg suffered a succession crisis, precipitated by the lack of a male heir to assume the throne, which led to the territories being sold by Duchess Elisabeth to Philip the Good of Burgundy.
The City of Luxembourg with its old quarters and fortifications was declared a UNESCO World Heritage Site in 1994 due to the exceptional preservation of the vast fortifications and the old city.