Monaco has the smallest coastline of any sovereign state in Europe, at roughly 4.1 kilometres.
The city-state occupies about 2.02 square kilometres on the French Riviera, beside the Mediterranean Sea. Its narrow coastal strip is heavily urbanised, with the Port Hercules area and reclaimed land extending the built-up shoreline. Monaco’s border with France surrounds it on the landward side, while its southern edge meets the Mediterranean.
The other wrong answers are landlocked European states. Vatican City is enclosed by Rome, San Marino is enclosed by Italy, and Liechtenstein lies between Switzerland and Austria. None of them has a coastline at all. Coastline measurements can vary slightly because different mapping scales produce different results, but Monaco is consistently recognised as Europe’s smallest coastal sovereign state.
Monaco is a constitutional monarchy ruled by the House of Grimaldi. It is also famous for the Monaco Grand Prix, held on streets around Monte Carlo and La Condamine.