There are many variations of this flower, the bellflower or campanula. In Romanian, they are generically called clopotei (translated as bells in English).
They were a nice surprise on our grass field at the end of May, with their beautiful flowers spread here and there, a bit of color among lots of green.
There are many kinds of the Campanula species, including many that can be planted in the garden. These look delicate and wildly beautiful.
Scientific name: Campanula patula