Monaco ( (listen); French pronunciation: [mnako]), officially the Principality of Monaco (French: Principaut de Monaco; Ligurian: Prinipatu de Mnegu), is a sovereign city-state and microstate on the French Riviera a few kilometres west of the Italian region of Liguria, in Western Europe, on the Mediterranean Sea. It is bordered by France to the north, east and west. The principality is home to 38,682 residents, of whom 9,486 are Mongasque nationals; it is widely recognised as one of the most expensive and wealthiest places in the world. The official language of the principality is French. In addition, Mongasque (a dialect of Ligurian), Italian and English are spoken and understood by many residents.With an area of 2.1 km2 (0.81 sq mi), it is the second-smallest sovereign state in the world, after Vatican City. Its 19,009 inhabitants /km2 (49,230/sq mi) make it the most densely-populated sovereign state in the world. Monaco has a land border of 5.47 km (3.40 mi) and the world's shortest coastline of approximately 3.83 km (2.38 mi); it has a width that varies between 1,700 and 349 m (5,577 and 1,145 ft). The highest point in the state is a narrow pathway named Chemin des Rvoires on the slopes of Mont Agel, in the Les Rvoires ward, which is 161 m (528 ft) above sea level. The principality is about 15 km (9.3 mi) from the border with Italy. Its most populous ward is Larvotto/Bas Moulins with a population of 5,443 as of 2008. Through land reclamation, Monaco's land mass has expanded by 20 percent. In 2005, it had an area of only 1.974 km2 (0.762 sq mi).

The principality is governed under a form of constitutional monarchy, with Prince Albert II as head of state, who wields immense political power despite his constitutional status. The Prime Minister, who is the head of government, can be either a Mongasque or a French citizen; the monarch consults with the Government of France before an appointment. Key members of the judiciary in Monaco are detached French magistrates. The House of Grimaldi has ruled Monaco, with brief interruptions, since 1297. The state's sovereignty was officially recognised by the Franco-Mongasque 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 state's first casino, the Monte Carlo Casino, as well as 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. Monaco is famous as a tax haven: the principality has no personal income tax and low business taxes. Over 30% of the residents are millionaires, with real estate prices reaching 100,000 ($116,374) per square metre in 2018.

Monaco is not formally a part of the European Union (EU), 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; before, it used the Monegasque franc, which was pegged, and exchangeable with, the French franc until the 1st of January 2002. Monaco joined the Council of Europe in 2004 and is a member of the Organisation internationale de la Francophonie (OIF). It is also the host of the annual street circuit motor race, the Monaco Grand Prix, one of the original Grands Prix of Formula One. The local motorsports association gives name to the Monte Carlo Rally, hosted in January in the French Alps. The principality has a club football team, AS Monaco, which competes in the French Ligue 1 and have become French champions on multiple occasions. A centre of research into marine conservation, Monaco is home to one of the world's first protected marine habitats, an Oceanographic Museum, as well as the International Atomic Energy Agency Environment Labs, which is the only marine laboratory in the United Nations structure.

Military or belligerent occupation, often simply occupation, is provisional control by a ruling power over a territory, without a claim of formal sovereignty. The territory is then known as the occupied territory and the ruling power the occupant. Occupation is distinguished from annexation and colonialism by its intended temporary duration. While an occupant may set up a formal military government in the occupied territory to facilitate its administration, it is not a necessary precondition for occupation.The rules of occupation are delineated in various international agreements, primarily the Hague Convention of 1907, the Geneva Conventions of 1949, as well as established state practice. The relevant international conventions, the International Committee of the Red Cross (ICRC) Commentaries, and other treaties by military scholars provide guidelines on such topics as rights and duties of the occupying power, protection of civilians, treatment of prisoners of war, coordination of relief efforts, issuance of travel documents, property rights of the populace, handling of cultural and art objects, management of refugees, and other concerns which are very important both before and after the cessation of hostilities. A country that establishes an occupation and violates internationally agreed upon norms runs the risk of censure, criticism, or condemnation. In the current era, the practices of occupations have largely become a part of customary international law, and form a part of the laws of war.