Short answers, pulled from the story.
The Inca Empire, officially known as Tawantinsuyu or the Realm of the Four Parts, was the largest empire in pre-Columbian America. Centered on Cusco in the Andean Mountains, it joined modern-day Peru with western Ecuador, western and south-central Bolivia, northwest Argentina, a tip of Colombia, and much of Chile.
The Inca civilization rose from the Peruvian highlands in the early 13th century, and the empire expanded between 1438 and 1533. The Spanish began their conquest in 1532, and by 1572 the last Inca state at Vilcabamba was fully conquered when the ruler Topa Amaru was captured and executed.
The Inca economy worked through reciprocity rather than currency or markets. Taxes took the form of a labor obligation called the mit'a, and in return the rulers granted access to land and goods and provided food and drink at feasts. The system rested on the vertical archipelago and on ayni, or reciprocal exchange.
Spanish conquistador Francisco Pizarro led the conquest with a force of 168 men, one cannon, and 27 horses. The Spanish captured the Inca Atahualpa at Cajamarca in 1532, collected a ransom of gold and silver, and executed him in August 1533.
The Inca built one of the greatest imperial states in history without the wheel, draft animals, iron, steel, or writing, as the anthropologist Gordon McEwan noted. They used mortarless stone blocks fitted so tightly that a knife could not pass through, and they recorded information on knotted strings called quipu.
Tawantinsuyu means the suyu of four parts, describing a union of four regions whose corners met at Cusco. The four suyu were Chinchaysuyu in the north, Antisuyu in the east, Qullasuyu in the south, and Kuntisuyu in the west. The Spanish renamed the land Peru.
Inca surgeons performed successful skull surgery, cutting holes in the skull to relieve fluid buildup and inflammation from head wounds. Survival rates ran from 80 to 90 percent, compared with about 30 percent before Inca times, and the chronicler Bernabe Cobo recorded that Spanish soldiers trusted indigenous surgeons over their own barbers.