Staring May 10th, 10:00 server time a wild Hydra will attack your cities. As it threatens your city and its citizens, you must burn the Hydras heads to keep your population safe. Start the adventure and try to collect 6 hydra heads. When you have captured 6 of the Hydra's heads you will be able to burn them and banish the creature. The Rewards for your heroic deed will be added to your extended inventory. Hurry up, as you have only until May 16th to banish the creature!
More info about the event can be found here.
Have fun and see you in the game!
Your Grepolis Team