Cinco De Mayo is just around the corner. Halo: The Master Chief Collection
Title Update 1 has a date related achievement tied to this celebration of Mexico's victory at the Battle of Puebla.
For the Elder Signs
achievement, you are required to view two unique sigils on the map Valhalla
. These sigils will appear on 8 special dates, Cinco De Mayo being one of them.
Look out for other reminders when the required dates approach.