Monastery Graveyard in the Snow, 1817 by Casper David Friedrich, Former National Gallery, Berlin.
Friedrich's ethereal landscapes have an uncanny calmness. People have very personal reactions to his art. For example, if you are religious, you might concentrate on the ruined church and what that means. If you are feeling isolated or lonely, the winter scene and bare trees, may be what you feel most moved by.
I could use some of this quiet.