The Inca civilization, which thrived from the early 15th century until the Spanish conquest in the 16th century, is renowned for its advanced architecture and extensive road systems. They developed impressive structures, such as Machu Picchu and Sacsayhuamán, showcasing their expertise in stone construction and engineering. The Inca constructed an intricate network of roads that extended over 25,000 miles, facilitating trade, communication, and military movement throughout their vast empire, which stretched across modern-day Peru, Ecuador, and Bolivia. Their sophisticated administrative systems and agricultural innovations also contributed to their success and enduring legacy, influencing future cultures in the region.