Snowdrop (Galanthus), fam. Amaryllidaceae.
There are over 100 species of snowdrops in the world. However, none of them grows wildly in our land, so they only occur in the city owing to the residents' efforts. The snowdrop's flowers can harmlessly survive the temperature –5 °С, which is a deadly frost for most other blooming plants. The bulbs (as well as other parts of the plant, evidently) are toxic.