Zardnaar
Legend
Perhaps more to the point, never travelled any distance upward (e.g. flew in a jet at 35000 feet) where the curvature of the horizon is more noticeable.
It's also far harder on land to perceive the effect that you can at sea where a distant ship slowly disappears below the horizon as it moves away from you; because while the sea is known to be level, on land it's far too easy for the mind to assume the distant object is simply going down the other side of a low hill.
I climbed a 700 Metre mountain. You can see the curve over the ocean.