GW2 The Big Boom in the Big City Achievement can be acquired by visiting Lion’s Arch when the Firework begins. This event takes place every 2 hours, and it starts 5 minutes before in game dawn according to Official Forum. Due to an unfortunate bug on the overflow servers, some people had been lucky enough to complete this achievement even before it began. Completing this achievement grants you achievement points, and Gift of the Dragon Bash reward, that contains three Horns of the Dragon Skins, which can be applied on another helmet.
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