Darkening of Valinor

Darkening of Valinor was the destruction of the Two Trees of Valinor, at the mound of Ezellohar west of Valmar, by Morgoth and Ungoliant approximately fifty years before the beginning of the First Age.

Quotes

"Then the Unlight of Ungoliant rose up even to the roots of the Trees, and Melkor sprang upon the mound; and with his black spear he smote each Tree to its core, wounded them deep, and their sap poured forth as it were their blood, and was spilled upon the ground. But Ungoliant sucked it up, and going then from Tree to Tree she set her black beak to their wounds, till they were drained; and the poison of Death that was in her went into their tissues and withered them, root, branch and leaf; and they died."

― The Silmarillion, Of the Darkening of Valinor