The Inca Empire was once the largest civilization of the Americas. Yet, there are major questions about its history and culture. This is in large part because the Inca did not have a written language. Much of their history was recorded by Spanish colonizers. They often lacked a clear understanding or appreciation of Inca culture. Additionally, the Inca lived high in the Andes Mountains, which were hard for archaeologists to reach.

Luckily, a relatively new kind of archaeologist can tell us more about this dynamic empire. This type of archaeologist works at high altitudes, and National Geographic Explorer Maria Constanza Ceruti is one of the top experts in this field. An Argentine with Indigenous Andean ancestry, Ceruti is a mountaineer who climbs cliffs in South America. She searches for signs of Inca society. In the late 1990s, she worked with a team that excavated an active volcano in Peru. There she and her team discovered mummified children. These are some of the best-preserved mummies ever found. The discovery revealed significant new information about Inca culture.

Mummies are important in Inca culture. Knowing why requires understanding their history. The Inca people began to consolidate into a small but organized community in the 1100s C.E. They established a capital in Cuzco. Manco Cápac, an Inca leader and founder of the dynasty, led his people to their new home, according to Inca legend.

Though some earlier emperors expanded the territory, the Inca would not become an empire until the early 15th century. That was when Viracocha Inca, who had already made a name for himself as a fierce warrior, came to power. Under his rule, the Inca began taking land south of their capital and bringing neighboring peoples under their control.

The Inca sometimes took land by force. Other times, they expanded into new areas peacefully, using diplomacy to gain trust. One way the Inca sometimes earned the support of other Indigenous people was by following their regional traditions. They sacrificed llamas and other animals to the local gods of newly acquired lands. Researchers say that animal sacrifice was an important Inca tradition.

At the same time, the Inca used force to maintain their holdings. They set up military posts to establish a permanent presence in the lands they took over. If they sensed that people were planning to resist, the Inca forced them to relocate. They sent groups of people who were loyal to the empire to live in the newly conquered areas, and they broke up cultural groups that began to resist by moving some of their members to areas that had already assimilated into Inca society.

The Inca Empire reached its peak when Viracocha Inca’s reign ended and his son Pachacuti’s began. One of their achievements was building new highways connecting the northern and southern areas of their empire. The system was intricate. It had suspension bridges made from vines and tunnels carved from rocks throughout the roadway, which was primarily used by the military.

The Inca also furthered developments in agriculture. They created a series of terraces in the mountains that were used as fields. This made it possible to grow a wide variety of crops at a high altitude. They also had complex irrigation systems that fed water to these fields. They used canals to conserve and clean water. The Inca became such expert growers that they needed to create storehouses to hold extra food. They kept track of their yields with quipus. These were a system of knots tied in the multicolored strands. They tracked information about food, people and more. While the Inca had no written language, some historians think the Inca used the quipu for words and narratives.

Inca kings built their own royal estates, which were large complexes of buildings with different functions. One of the most famous royal estates is Machu Picchu, a palace likely built by Emperor Pachacuti Inca Yupanqui. The many buildings at Machu Picchu include temples, agricultural structures, administrative buildings and residential houses. The site also includes courtyards and grottos that were likely used for ceremonies and community activities.

Inca kings remained important to the Inca people even in death. Like the ancient Egyptians, Inca leaders were mummified to help the body pass into the afterlife. But instead of being permanently buried like the Egyptians, Inca mummies were brought out during important festivals. Inca mummies were dressed in fancy clothing. They were often given goods and food in return for helping people reach their gods.

In the 1490s, Huayna Capac took over control of the Inca Empire. He later contracted a disease that likely came from Spanish colonizers in present-day Ecuador. He died, leaving the empire under the control of two brothers, Atahualpa and Huascar. The brothers fought, and Atahualpa took control of the whole empire. But his victory was short-lived. Spanish conquistadors led by Francisco Pizarro took Atahualpa prisoner in a surprise attack, eventually killing him. The Spanish then installed a series of rulers under the control of Spain. The Inca resisted by continuing the care of mummified kings until 1559. That year, Spanish leaders took all of the mummies they could find and displayed them for a time for Spanish colonists in Lima, the colonial capital.

National Geographic Explorer Ceruti did not find the mummies of Inca kings. But the child mummies she did find are important parts of Inca culture and history. Experts believe that these children were probably sacrificed to the gods in special ceremonies called capacocha. The sacrificial ritual sites were on high mountain peaks because the Inca wanted to get as close to the gods as possible. Examiners found that children who were sacrificed were well cared for. They wore special clothing and metal jewelry. The capacocha is a unique part of Inca culture, and modern understanding has grown thanks to Ceruti’s work. “Fortunately we have mummies that can speak if we can listen to them properly,” Ceruti once said.

Ceruti has also risen to the challenges of working in a male-dominated field. She continuously calls out bullying of women in research and works to increase the visibility of women in science. She has a body of work that includes 25 books, hundreds of articles and publications and ongoing public speaking events. She says it is in her blood to continue climbing mountains and making new discoveries. Through her work, Ceruti has helped deepen our understanding of the Inca and preserve knowledge of their culture for future generations.