This beautiful card of Tallinn was sent by Ella via postcrossing [EE-98433]. She lives there with her family. She tells me that on the card we can see the old town of Tallinn, which is an Unesco World Heritage Site, in White Nights. "In June we have White Nights. It is not dark in night: on the card you can see the darkest time (you can read newspaper without extra light)."
Sounds like an incredible experience! I hope I will see it for myself someday :)