On May 1st 2004, the largest enlargement of membership in the history of EU finished. Ten Eastern European countries, Poland, Czech, Slovak, Hungary, Slovenia, Lithuania, Latvia, Estonia, Cyprus, and Malta joined the EU officially on that day.

• 2004年5月1日，欧盟历史上最大的一次东扩完成，东欧10国，波兰、捷克、斯洛伐克、匈牙利、斯洛文尼亚、立陶宛、拉脱维亚、爱沙尼亚、塞浦路斯、马耳他正式加入欧盟。