Longest border of France

If someone asked you which country shares the longest land border with France, you would probably guess Spain or Germany.

The reason lies in French Guiana, an overseas department and region of France located on the northern coast of South America. Unlike former colonies, French Guiana is an integral part of France, meaning its borders are also France's borders.
As a result, the border between French Guiana and Brazil stretches for approximately 730 kilometres (454 miles), making it France's longest land border—longer than its border with Spain.

Most of the frontier runs through the Amazon rainforest, following the Oyapock River for much of its length. The only road crossing is the Oyapock Bridge, which connects the Brazilian town of Oiapoque with Saint-Georges-de-l'Oyapock in French Guiana.

It's one of the world's most surprising geographical facts: although France is best known as a European country, its longest land border is actually located thousands of kilometres away in South America.