Using only SVG, this visualization depicts a stylized sunrise and sunset over a layered, rolling landscape. Animated radial and linear gradients shift the sky through aliceblue, steelblue, indigo, and midnightblue tones over a 15-second cycle, while a `<circle>` sun moves vertically via SMIL `<animate>` tags. Two cubic Bézier `<path>` elements form the terrain, each filled with animated linear gradients that synchronize with the sky. The code directly embeds all timing and color keyframes in the SVG markup, relying on native SMIL animation rather than JavaScript libraries.