The empire known for its vast road system and Incan architecture is the Inca Empire. Centered in modern-day Peru, the Inca Empire was the largest empire in pre-Columbian America, known for its advanced engineering and architectural prowess. They constructed an extensive network of roads, totaling about 25,000 miles, facilitating trade and communication across rugged mountainous terrain. The Incas were also renowned for their impressive stone structures, such as Machu Picchu, showcasing their sophisticated agricultural techniques and social organization, allowing them to thrive in challenging environments.