Final answer:
The historical capital of the Inca empire is Cuzco, now a UNESCO World Heritage Site and the center of Incan civilization. Renowned for its architecture, it includes the famous Machu Picchu, which exemplifies the Inca's engineering prowess.
Step-by-step explanation:
The historical capital of the Inca empire, which is now a UNESCO World Heritage Site, is Cuzco, located in present-day Peru. This city was the center of the Incan civilization, one of the most powerful and extensive pre-Columbian empires in the Americas. Despite being conquered by the Spanish in the 16th century, the rich history and cultural significance of Cuzco, along with the Inca’s architectural acumen, is well-preserved and can be especially seen in the iconic ruin of Machu Picchu. Built around 1450 as a ceremonial city and a royal retreat for Inca ruler Pachacuti Yupanqui, Machu Picchu is situated high in the Andes Mountains at an altitude of nearly 8,000 feet. It is renowned for its terraced fields, polished stone constructions without the use of mortar, and intricately designed buildings that harmonize with the natural landscape. The Inca were skilled at adapting their architecture to the rugged Andean terrain, a testament to their engineering abilities.