A 360-degree panorama of Titan, taken five miles up, shows fuzzy streaks—possibly methane fog—along the border between the lowlands and lighter highlands at left. Features near that boundary resemble barrier islands and sandbars, while the dark regions at right may be flood basins coated with tarry sediment; they might fill with liquid methane that then soaks into the ground. The plateau at middle right, like most high regions on Titan, probably consists mostly of water ice. Geologic activity must rebuild such formations; otherwise they would erode away due to wind and rain.