Very talented and beautiful woman. And yea, that was "Nothing Else Matters" by Metallica at the end of the 1st one done by a string quartet.
Also, the same song is playing at the end of the second one.
Actually Ksenia takes part in a nation contest "Ukraine has talents" where I saw it for the first time. She is one of the main contender for a win. In fact, a sand animation is quite a rare art: there are only a few people, may be 4 or 5, in the world who is practicing it. Both videos are variations on a theme of war, namely, A Great Patriotic War 22.06.41-09.05.45 (WWII, if you like). And no doubts she has managed to find a passforward to hearts of the majority of spectators. It turned out our citizens are still sensitive to such theme.