Welcome to Mystery Class 2019*

March 18: It's time for the first set of Continent, Country, and City clues. Week by week, these clues reveal fun facts to help you progressively narrow your search. More...



How to Participate
Mystery Class Photoperiod Map
Reasons for Seasons: Model

Revolving Earth


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: Due to budget limitations, our spring 2019 Mystery Class challenge is a replay of a previous year's challenge. We will reveal the locations of the 10 Mystery sites on Monday, April 15th but will not hold a year-end contest.