This is a beautiful postcard of Vienna, sent by Kamila from Poland, where she is back after vacations in the Austrian capital. Many thanks for the incoming!
I will have to check out my cards from Poland, as I might have completed the beautiful series of Easter Eggs, which I just learned writing this, I an ongoing series spanning different years. Wielkanoc has two new stamps in 2017, the one above, and a white egg. The following pictures are from the informative website of the Polish Post.