Mystery Class is a global game of hide-and-seek. Follow photoperiod clues to search for ten secret sites around the world. Track sunlight to solve a mystery—and discover the reasons for seasons along the way.
*Please note: Our spring 2020 Mystery Class challenge is a replay of a previous year's challenge. You have open access to all of the season’s clues (Weeks 1-11). We will reveal the locations of the 10 Mystery sites on April 13, 2020.