It was the treaty that created the European Union and laid the foundation for the single European currency.
It introduced a common foreign and security policy and allowed people from member countries to move freely within the union.
Its members also agreed to work towards EU-wide policies on everything from the environment to immigration, drugs and terrorism.
And it was signed in Maastricht, a small Dutch town of 120,000 people wedged between Germany and France – the ideal symbolic location.
But twenty five years later the optimism expressed by the finance and foreign ministers who gathered for the signing ceremony there in February 1992 seems hopelessly misplaced.
The President of the European Council at the time, who was also the prime minister of Portugal, called it “historic”.
“The treaty we are about to sign is a decisive step forward in the path towards the European Union, an unparalleled process in contemporary history,” Aníbal Cavaco Silva had said in a ceremonial speech.
One of the main economic criteria for the 12 states who signed up to it that day – and those that joined later – was to have no more than 60 percent of debt as a proportion of their GDP.
Crucially it was the failure of many eurozone states to stick to this debt rule which caused the great financial crisis in 2009.
Ten years after Maastricht was signed the first euro notes inside the union rolled out of cash machines in 2002 to great excitement.
But now the currency’s very existence in eurozone states such as Greece is being questioned.
And just as the EU celebrates its milestone anniversary, the UK is on the verge of filing its Brexit divorce papers, leading many to fear that other EU states may also quit.