We usually think of a crack as a blemish. A cracked window needs to be replaced. The cracked patina of old paintings is reluctantly accepted as a proof of age. In The Fall of the House of Usher, Edgar Allan Poe has turned the crack in a wall into a bad omen of the worst kind. Roman Polanski did likewise with cracks in concrete in his film Repulsion. Are cracks really that bad?
In geologically active regions like Iceland, cracks happen more often than elsewhere, and on a much larger scale.
The cracked wall above is from a house on the Westman islands that was half covered by the lave flow from 1973 and is kept as is as a monument.
Cracks appear everywhere. In individual rocks,
in the ground like here near a lava tube,
vertically, splitting entire mountains,
or here, where the crack is literally between the American and European continent.