Today's the day to either unlock or make 50% worth of progress towards the Elder Signs achievement in the Title Update 1 for Halo: The Master Chief Collection , specifically available in. April 22nd celebrates 'Earth Day' and is a day dedicated to keeping the Earth clean as events are demonstrated to support environmental protection.There's a few different solutions posted up on how to pop this achievement which looks very straight-forward to do. Of course, if you just want to knock this out the "offline" way then there's always that option too.Fire up Halo: The Master Chief Collection , selectand make progress towards the achievement or view the last sigil you need for an almighty ten Gamerscore. You have until the end of the day to do so.We've got the full list of Halo: The Master Chief Collection achievements - check the list for guides to unlocking them.