Perhaps most unique about Inca civilization was its thriving existence at altitude. The Incas ruled the Andean Cordillera, second in height and harshness to the Himalayas. Daily life was spent at altitudes up to 15,000 feet and ritual life extended up to 22,057 feet to Llullaillaco in Chile, the highest Inca sacrificial site known today. Mountain roads and sacrificial platforms were built, which means a great amount of time was spent hauling loads of soil, rocks, and grass up to these inhospitable heights. Even with our advanced mountaineering clothing and equipment of today, it is hard for us to acclimatize and cope with the cold and dehydration experienced at the high altitudes frequented by the Inca. This ability of the sandal-clad Inca to thrive at extremely high elevations continues to perplex scientists today.