Trebek has always moderated the National Graphic World Championship, which this year was hosted by Google.
Teams from 18 countries participated; on Wednesday, the top three countries -- Canada, Chinese Taipei and Russia -- answered questions in a game show format.
In the end, it was the team from Russia who won the top prize.
"When we discovered this geography bee, we thought this would be a perfect avenue for us to get more students interested in geography," said Brian McClendon with Google Earth.
Trebek appeared at the event after recovering from a burglary attempt on his hotel room early Wednesday morning. Trebek says he caught a woman stealing money and jewelry from his San Francisco hotel room.