In this paper I will on the one hand explore and challenge Heidegger’s notion of the unity of the world (SZ, 69) by means of the experience of a great loss. And on the other hand, I will reveal how world’s supposed unity shows the impact of a great loss, however. Hereby I will not contest Heidegger’s constituents of world (and Dasein) which are the ‘Existenzialien’, i.e., ontological characters (of Dasein). But I will show that it is exactly because of the Existenzialien’s equi-originary character that Heidegger’s world can fail to be a unity for us. The notion ‘Gleichursprünglichkeit’ (equiprimordiality (Macquarrie & Robinson) or equi-originarity (Blattner)) plays an import role in Heidegger’s early writings, especially Sein und Zeit. By showing that a phenomenon’s origin(arity) is interdependent and that it is constituted by this non-hierarchal relation, equi-originarity objects, among others, the idea or rather assumption that phenomena ought to be grounded in one single ground (Urgrund). For instance, in a 1927 lecture on phenomenology, Heidegger shows that self and world always imply each other. In Sein und Zeit, however, Heidegger differentiates that. Here he shows that world is constituted by several Existenzialien, such as: understanding, ‘Befindlichkeit’, discourse, being-with and being-in. In this paper, I will explore that if a loss befalls us, it is in part because of the world’s supposed unity constituted by the Existenzialien, among which: understanding, ‘Befindlichkeit’, discourse, being-with, being-in, that we can experience what has happened. While on the other hand, the experience that ‘we fail to find the words’, ‘we don’t get it’, and ‘a world has gone’ shows (in part) that Heidegger’s world can fall apart; or has never been a unity, after all?