How open is the rest of Europe to David Cameron's EU reform plans and can he win their support? The BBC's Laurence Peter examines the diplomatic battle.
EU ministers approve plans to establish a naval force to combat people-smugglers operating from Libya.
What is the Transatlantic Trade and Investment Partnership and why does it matter?
How MEPs from 28 nations work together
Maps showing how EU has grown over decades
How the EU is coping with irregular migrants
What are migrants living in another EU country entitled to?
Rules governing movement of people in EU
Key issues explored following EU's biggest election yet
Video tour behind the scenes at EU institutions
Will Juncker's new EU fund lure investors?
Eurosceptic surge and other election landmarks
The big issues in Europe's election - in stark detail
Losing European identity in crisis-hit Greece