Also known as: 地平線, 地平线, 水平線, 水平线
The horizon is the border between Earth (Planet) and Sky. As the horizon is usually obscured by trees, mountains, buildings, etc., it is most visible in settings dominated by the Ocean or other featureless terrain.
When the outline of a city is visible over the horizon, this is known as a Skyline.
If the horizon is tilted with respect to the picture frame, the result is a Dutch Angle.