Monaco. Monaco, officially the Principality of Monaco, is a sovereign city-state, country, and microstate on the French Riviera in Western Europe. France borders the country on three sides while the other side borders the Mediterranean Sea. Monaco is about 15 km from the state border with Italy. Monaco has an area of 2.020 km 2, making it the second-smallest country in the world after the Vatican. Its population as of 2018 is 38,682. With 19,009 inhabitants per square kilometre, it is the most densely-populated sovereign state in the world. Monaco has a land border of 5.47 km, the world's shortest coastline of approximately 3.83 km, and a width that varies between 1,700 and 349 m. The highest point in the country is a narrow pathway named Chemin des Révoires on the slopes of Mont Agel, in the Les Révoires Ward, which is 161 metres above sea level. Monaco's most populous Quartier is Monte Carlo and the most populous Ward is Larvotto/Bas Moulins. Through land reclamation, Monaco's land mass has expanded by 20 percent; in 2005, it had an area of only 1.974 km 2. Monaco is known to be the most expensive and the wealthiest place on Earth, Vatican City excluded, due to its tax laws. In 2014, it was noted that about 30% of the population was made up of millionaires. Monaco is a principality governed under a form of constitutional monarchy, with Prince Albert II as head of state. Although Prince Albert II is a constitutional monarch, he wields immense political power. The House of Grimaldi has ruled Monaco, with brief interruptions, since 1297. The official language is French, but Monégasque, Italian, and English are widely spoken and understood. The state's sovereignty was officially recognised by the Franco-Monegasque Treaty of 1861, with Monaco becoming a full United Nations voting member in 1993. Despite Monaco's independence and separate foreign policy, its defence is the responsibility of France. However, Monaco does maintain two small military units. Economic development was spurred in the late 19th century with the opening of the country's first casino, Monte Carlo, and a railway connection to Paris. Since then, Monaco's mild climate, scenery, and gambling facilities have contributed to the principality's status as a tourist destination and recreation centre for the rich. In more recent years, Monaco has become a major banking centre and has sought to diversify its economy into the services sector and small, high-value-added, non-polluting industries. The state has no income tax, low business taxes, and is well known for being a tax haven. It is also the host of the annual street circuit motor race Monaco Grand Prix, one of the original Grands Prix of Formula One. The principality has a club football team, AS Monaco, who have become French champions on multiple occasions. Monaco is not formally a part of the European Union, but it participates in certain EU policies, including customs and border controls. Through its relationship with France, Monaco uses the euro as its sole currency. Monaco joined the Council of Europe in 2004. It is a member of the Organisation Internationale de la Francophonie. Main article: History of Monaco Monaco's name comes from the nearby 6th-century BC Phocaean Greek colony. According to an ancient myth, Hercules passed through the Monaco area and turned away the previous gods. As a result, a temple was constructed there, the temple of Hercules Monoikos. Because the only temple of this area was the House of Hercules, the city was called Monoikos. It ended up in the hands of the Holy Roman Empire, which gave it to the Genoese. An ousted branch of a Genoese family, the Grimaldi, contested it for a hundred years before actually gaining control. Though the Republic of Genoa would last until the 19th century, they allowed the Grimaldi family to keep Monaco, and, likewise, both France and Spain left it alone for hundreds of years. France did not annex it until the French Revolution, but after the defeat of Napoleon it was put under the care of the Kingdom of Sardinia.