-Linear perspective: Even looking with one eye, two parallel lines come together in the distance as in looking down a long highway on flat ground.
-Interposition: When objects overlap, the overlapping object appears closer and the object being overlapped appears farther away.
-Light and shadow: Lit objects appear closer then objects in shadows.
-Texture gradient: Objects in sharp detail seem closer than objects with poorer detail.
-Atmospheric perspective: We perceive clearer objects as closer than those covered in haze or clouds.
-Motion parallax: Objects moving at high speed seem closer than slower moving objects.
Convergence and retinal disparity are depth clues which are a result of having two eyes, but there are several monocular clues as well.