"One of the construction blocks from which the pier was fashioned weighs an estimated 440 tons (equal to nearly 600 full-size cars) and several other blocks are between 100 and 150 tons. The quarry for these giant blocks was on the western shore of Titicaca, some ten miles away. There is no known technology in the ancient Andean world that could have transported stones of such massive weight and size. The Andean people of 500 AD, with their simple reed boats, could certainly not have moved them. Even today, with modern advances in engineering and mathematics, we could not fashion such a structure." source: sacredsites .com
The 440 ton estimate has been disputed. The largest stone at Tiahuanaco is probably about 130 tons. The larger estimate seems to have been the result of a misrepresentation that has been repeated without scrutiny by many sources. A similar incident seems to have happened in the case of the Baalbek stones that have been estimated at over 1,000 tons. The more reliable estimate for the trilithon stones is probably 700 to 900 tons. The most reliable source for these estimates is the stone themselves. If it turns out they are larger the bigger estimates can be restored.
Tiahuanaco is approximately 12,500 ft. above sea level. the air is much thinner than at sea level. Farming is much tougher and people who are not accustomed to the altitude tire easy from lack of oxygen. Even people who are accustomed to the altitude would still have a hard time coping with the environment let alone moving stones over 100 tons over rough terrain.
Ollantaytambo is 9,000 ft. above sea level and it appears to have 6 colossal stones 50 tons although I don't have exact dimensions.
Some believe the walls were a form of fortification. Like much Inca stonework there is still mystery surrounding how they were constructed. The structure is built in such a way that a single piece of paper will not fit between many of the stones. This precision, combined with the rounded corners of the limestone blocks, the variety of their interlocking shapes, and the way the walls lean inward, is thought to have helped the ruins survive devastating earthquakes in Cuzco. The longest of three walls is about 400 meters. They are about 6 meters tall. Estimated volume of stone is over 6,000 cubic meters. The largest limestone block is estimated at 128 tonnes. source: "Seventy Wonders of the Ancient World" edited by Chris Scarre 1999
Pisac agricultural terraces and ruins
The drainage canals and air ducts of Chavín de Huántar far exceeded simple engineering. The central platform was 11 meters tall. The southern platform was 16 meters tall. The northern platform was 14 meters tall. source: "Seventy Wonders of the Ancient World" edited by Chris Scarre 1999
These include lines which ran absolutely true for 6 miles or more.
It is difficult to imagine how the islanders moved such a large statue from the quarry four miles (six kilometers) away; Paro is the island's largest transported Moai. Lying face down, toppled from its Ahu, Paro weighs 82 tons and is 32.45 feet (9.89 meters) long.
Easter Island is only 64 square miles. It has a very limited amount of fresh water. There is a small lake in the top of the dormant volcano however when rainfall is low that probably doesn't provide as much water. It would be helpful to know what the climate was like while the people that lived there were moving those stones. It is hard to imagine primitive people having much spare time in such a remote area. simply growing food or fishing should take up a lot of their time.
107 Wonders of the Ancient World (Blog entry)
One Hundred and Seven Wonders of The Ancient World: Introduction
Middle East Wonders of The Ancient World
African Wonders of The Ancient World
European Wonders of The Ancient World
South American Wonders of The Ancient World
North American Wonders of The Ancient World
Asian Wonders of The Ancient World
Preliminary Conclusions For One Hundred and Seven Wonders of The Ancient World
Prophets and Mystics