In groups, students prepare quizzes and puzzels about their city, school or themselves (they have to say what is the activity about). After that, they post the link of the activity. Then, the other students answer and post the answer screen shot as an evidence. We open subpages per country and publish the questions while the answers (screen shots) are posted by the pupils in Twinboards in each subpage.

https://www.jigsawplanet.com/

https://puzzel.org/en/