European politicians are celebrating the launch of a new way to manage the European Union.
The Lisbon Treaty has come into force and EU leaders travelled to the Portuguese capital for a ceremony to mark the occasion.
The main goal of the treaty is to reform how the EU functions, including voting rights, now it has been expanded to 27 members.
Talks on reforming European institutions began in 2001 but it has been a difficult process trying to get all member states to agree to the details.
All EU countries had to ratify the text before it could be adopted, and the Czech Republic was the last country to do that.
The treaty created a permanent “president” and foreign affairs “chief”.
Critics, however, fear a loss of national power to Brussels and there has been a big debate on whether the EU is democratic enough.