Achievements are granted for achieving a certain task. In order to find your achievements you need to go to your profile and it will show your most valued achievements and a link to your achievements page.
When you are on the achievements page the following is shown: The amount of achievements you've acquired. Your global rank when it comes to achievements. Your local rank when it comes to achievements. Your most valuable achievements. Your most recent achievements. All achievements ordered in categories and separated on whether you've acquired an achievement or not for that category.
In order to see what the requirements are for each achievement you simply hover your mouse over the the achievement and a notification will drop down revealing the requirements. You can also look through the categories in order to see what achievements you have acquired and those which are not yet acquired.
Category Military (31 achievements)
Category Medals (12 achievements)
Category Society builder (17 achievements)
Category Social (54 achievements)
Category Tournament (16 achievements)
Category Equipment (10 achievements)
Category Collector (14 achievements)