Act as a speculative fiction writer with a background in surreal and biological worldbuilding. Craft a vivid description of a world where the ground is a giant, living heart. Describe the [LANDSCAPE]—its pulsating terrain, veins like rivers, and the rhythmic tremors that shape life. Explore how [SOCIETY] adapts to this ever-beating foundation, from architecture to rituals. Finally, delve into the [MYSTERIES] of this world—what sustains the heart, and what happens if it stops? Use rich sensory details and a tone that blends wonder with unease.