Negotiating height differences comfortably and using space efficiently is the primary function of stairs. Their invention is not attributed to a single individual or specific civilization; rather, they evolved independently across various cultures throughout history. The earliest evidence of staircases is found in ancient Mesopotamia, Egypt, and the Indus Valley Civilization, with notable examples including the Mesopotamian ziggurats and the Great Pyramid of Giza. The Greeks and Romans further refined the design, and during the medieval period, spiral staircases became common in castles for defensive purposes. The Renaissance introduced even more elaborate and decorative examples crafted from stone, marble, and, later, iron and steel. In modern times, innovations in concrete and precast components emerged, reflecting advancements in materials and engineering. Floating staircases, for example, have become a major trend by visually expanding spaces and enhancing natural light within an environment. They are characterized by an elegant, minimalist design where the treads appear to float in midair without visible support, anchored to a single wall.
