Saint Martin is the unique Caribbean island that is divided between two nations: the northern French side (Saint-Martin) and the southern Dutch side (Sint Maarten). This division dates back to the Treaty of Concordia in 1648. The Dutch side, Sint Maarten, is known for its vibrant nightlife, duty-free shopping in the capital of Philipsburg, and the famous Maho Beach, where planes fly low over tourists to land at Princess Juliana International Airport. Despite being two separate territories with different cultures and languages, there is no hard border between the two sides, allowing travelers to move freely between the French and Dutch parts of the island.