European Parliament, Strasbourg
In January 2005, MEPs voted to approve what was then still called the "treaty establishing a constitution for Europe".
After voting on a series of amendments, MEPs voted for the report as a whole.
Despite strong applause from many MEPs, the result was jeered by a large group of banner-waving Eurosceptics.
Amid the noise, the then President of the European Council, Luxembourg's Prime Minister Jean-Claude Juncker, struggled to speak.
This was just the start of a long and arduous political voyage for the treaty - rejected by voters in France and the Netherlands, it was slimmed down to become the Lisbon Treaty.
The Lisbon Treaty removed references to a "constitution" and increased the number of opt-out abilities for certain countries in certain policy areas. However, it was rejected by Irish voters in a referendum in June 2008.
As with any other treaty, it must be ratified by all member states before it can come into force.