An underhill temple is a type of religious structure built partially or entirely underground or inside a hill or mound. This form of temple architecture is found in various cultures and civilizations, often associated with ancient or indigenous religious practices. Underhill temples have been constructed for different religious purposes, including burial sites, sanctuaries, and places of worship. The design of underhill temples provides a sense of closeness to the earth and nature, and they are often intricately linked to the cosmological beliefs of the communities that built them. The natural landscape and topography are essential factors in the positioning and construction of underhill temples, reflecting the harmony between human spirituality and the environment. The underhill temple offers a unique perspective on ancient religious practices and the integration of sacred spaces into the natural world. Studying these structures provides valuable insights into the cosmological concepts, spiritual rituals, and burial practices of ancient cultures, enriching our understanding of the diverse expressions of human spirituality throughout history. Examples of underhill temples can be found in various regions, including ancient India, the Celtic cultures of Europe, and the indigenous societies of the Americas.