January 27 - April 13, 2020*

*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.

January 27 - April 6

Photoperiod Clues
Every Monday for 11 weeks, sunrise/sunset data will be provided from all 10 sites. Use it to calculate photoperiod.  Then use photoperiod to estimate the latitude of each site.

    March 9 Time Clues
As the spring equinox approaches, time clues will be posted on March 11 to help students estimate the longitude of each site.
March 16 - April 6

Continent, Country, City Clues
During the final 4 weeks, clues will be provided to help you narrow your search from continent, to country, and then to city. Research to pinpoint locations.

  April 13 Mystery Sites Revealed
Locations of the 10 Mystery sites are posted.