The term "Subterranean World" refers to environments located beneath the Earth's surface, including caves, tunnels, and underground ecosystems. These areas can host unique geological formations, such as stalactites and stalagmites, and are often home to specialized organisms that have adapted to dark, humid conditions. Subterranean worlds can also include human-made structures like subways and mines, which serve various purposes, from transportation to resource extraction. These underground spaces play a crucial role in geology, ecology, and even archaeology, providing insights into Earth's history and the evolution of life.