Zelensky Vs Putin: Why Russia flared up on Ukraine?

Russia-Ukraine War has entered the 34th day where the conflict has been intensified. Ukraine's city Mariupol is facing heavy explosions and bombing. While Ukraine is also putting in its best possible efforts. The Russian army was stopped in the capital Kyiv. Amid this war, Zelensky seems to keep various conditions in front of Russia while Putin is giving constant threats of huge war to Ukraine. Watch this video.