Benelux
On 25 july 1921, the Belgium-Luxembourg Economic Union was established, a treaty which is still upheld. Following World War II, the harsh economic climate in Europe led to a further desire for economic cooporation between Belgium, Luxembourg and Netherlands. The Benelux Customs Convention was signed in London on 5 September 1944, by the three governments-in-exile in London. The treaty officially entered into force in 1948. On 1 November 1960, the customs union was superseded by the Benelux Economic Union treaty, signed in The Hague on 3 February 1958. The treaty contributed to the founding of the European Union (EU), serving as a proving ground for succesful economic cooperation within Europe.