European Union leaders are gathering in Rome on Saturday to celebrate the 60th birthday of the world's largest political and economic bloc - the same place its key players met in 1957 to set up the organization.
There are plenty of reasons for the EU to celebrate yet another milestone anniversary though the landmark achievement is likely to be somewhat bittersweet given the unprecedented challenges in the bloc's wake.
The rise of populism and anti-EU feeling throughout its own citizens, military conflict in the Middle East and eastern Europe as well as Britain's decision to quit the bloc all threaten to overshadow the event.
As EU member states prepare for the bloc's future, CNBC takes a look back at some of the EU's landmark moments:
The European Economic Community (EEC) was founded when representatives from Belgium, France, Germany, Italy, Luxembourg and the Netherlands signed the Treaty of Rome on March 25 1957.
Six decades later and the modern construction of the European Union stands tall, if not totally united.
The European Monetary System (EMS) introduced the European currency unit (ECU) as well as the exchange rate mechanism (ERM). This allowed national currencies to base an exchange rate on the ECU.
Every member state elected to join, except the U.K.
The demise of the so-called "iron curtain" in Communist eastern Europe resulted in the collapse of the Berlin Wall in 1989, Germany's reunification in 1990 and the fall of the Eastern Bloc two years later.
In 1992, the European Economic Community officially became known as the European Union following the signing of the Maastricht Treaty.
The euro was formally established in 1999, 20 years after the EMS unveiled the ECU and ERM.
Three years after the launch of the single currency, 11 countries had replaced their national currencies with euro notes and coins.
Sweden, Denmark and again the U.K. decided not to sign up.
In 2004, the European Union welcomed its biggest enrollment to date as 10 countries signed up to the bloc.
Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia all joined the EU.
The financial crisis in 2008 sparked a global reaction which inflicted several European countries and led to European Central Bank (ECB) President Mario Draghi to defiantly claim in 2012 that the central bank was willing to do "whatever it takes to preserve the euro (and) believe me it will be enough."
EU countries which had borrowed heavily for many years became unable to finance government debt during the crisis. Greece, Portugal, Ireland, Spain and Cyprus all required support from fellow euro countries, the ECB and the International Monetary Fund.
In 2012, the EU received the Nobel Peace Prize for advancing the causes of peace, democracy, reconciliation and human rights across the continent.
Britain held a referendum on Thursday 23 June 2016 to decide whether to leave or remain in the EU. More than 30 million U.K. citizens voted although ultimately the Leave campaign secured victory with 51.9 percent of the vote.
U.K. Prime Minister Theresa May is due to activate the two-year negotiation process to divorce the bloc just four days after the EU turns 60 years old.