I intend to create this club this summer. Do you have suggestions on how this should be done?
I'm thinking to several approaches:
1. Similar with europapostcards where you add stamps to unesco sites. You select the site and the stamp that you send. Also with the limitation that you receive the stamps only once.
2. You only select the unesco site and after that you can send something (anything) related to that site. A unesco related postcard, a unesco stamp on any postcard, or other items like souvenirs?