Euler line

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Let $ABC$ be a triangle, points $H, N, G, O, L$ as $\triangle ABC$ 's orthocenter, nine-point center, centroid, circumcenter, De Longchamps point respectively, then these points are collinear(regardless of $\triangle ABC$ 's shape). And the line passes through points $H, N, G, O, L$ is called as Euler line, which is named after Leonhard Euler.