The primary reason we can't readily see the Earth's curvature is due to its vast size relative to our perspective. The curve is subtle and gradual, making it difficult to perceive from ground level, especially over short distances. It becomes noticeable at higher altitudes, such as from airplanes or space, where the curvature spans a larger portion of our field of view, according to Instagram user The Engineer's Mess. The Earth is enormous, with a circumference of approximately 40,075 kilometers