Famed as a playground for the rich, replete with a casino and an annual car race that roars through its narrow streets, Monaco has been ruled almost continuously by the Grimaldi dynasty since 1297.
Its monarch Albert II and his wife Charlene on Wednesday announced the birth of their twins Gabriella and Jacques, with the baby prince next in line to the throne despite being born two minutes after his sister.
Here are some facts about Monaco:
The principality consists of less than two square kilometres (0.75 square miles) of steep and rocky real estate carved out of France's Mediterranean coast. It is the second smallest state in the world after the Vatican.
In 1861 it was recognised as an independent state under a treaty with France, with which it has been closely associated ever since.
It has a population of around 37,000, though only around 8,000 are Monegasques (born, at home or abroad, to a Monegasque father). Most of the other residents are either French or Italian.
Monaco is not a member of the European Union, but has a customs union with France and shares its currency, the euro. It does not levy income tax, which - along with its sunny climate - has encouraged many celebrities and wealthy businessmen to settle there.
Over the last 50 years buildings have come to cover virtually the whole of the territory.
To generate more space the government began reclaiming land from the sea in the 1970s.
One of the best-known buildings is the legendary Monte Carlo casino, which opened its doors in 1856, triggering the principality's transformation into a magnet for the mega-rich.
Motor racing is also closely associated with Monaco. The first Monaco Grand Prix was held in 1929.
Prince Albert ascended to the throne following the death of his father Prince Rainier in 2005.
Rainier was the widower of Hollywood actress Grace Kelly, who died in a car crash in 1982.
Albert has two sisters, Caroline and Stephanie.
Caroline, who lost her second husband Stefano Casiraghi in a 1990 motorboat accident, was the heir to the throne before the birth of Albert's twins.