#1 Sacsayhuaman, Cusco, Peru
For me this site is at the top, without hesitation.
The following is from: www.ancientufo.org/2017/06/stunning-walls-sacsayhuaman/
“Near the city of Cuzco, more than 3500 meters above sea level, the Sacsayhuaman amazing walls first fascinated the Spanish conquistadores and still leave archaeologists puzzled.
It rests on an artificially leveled mountaintop, and consists of three outer lines of gargantuan walls, 1,500 ft long and 54 ft wide, surrounding a paved area containing a circular stone structure believed to be a solar calendar. The ruins also include a 500,000-gallon water reservoir, storage cisterns, ramps, citadels and underground chambers.
Although a substantial part of the walls has been removed over the ages (as much as 3 meters along their lengths according to archaeologists), what remains does so because it was too large to move. Funny isn’t it?”
I have personally explored this site on two separate occasions. There are thousands of large stones (one estimated at 300 tons) that have been assembled into a ‘fortress” without the use of mortar. All of the joints are so precise that not even a human hair can penetrate the seams! Some of the stones have a dozen or more angles and yet the adjacent stones fit the angles perfectly.
The site is located approximately 500 feet above the city of Cuzco at an elevation of over 11,000 feet. The slope from the city to the site is very steep, in some areas as much as 40 degrees. It has been determined that the quarry site is located on the other side of the valley at a distance of over 7 miles (as reported by a local guide.
While there is ample evidence that the Incas used the site as a defensive position against the invading Spanish, it is ludicrous to believe that they anything to do with the construction.
Who and when this construction was accomplished is a mystery. Similar construction can be viewed (albeit on a much smaller scale) both in the City and at Maccha Picchu. One of the stones in Cuzco has 32 angles! At Maccha Picchu there are three distinct types of construction. The oldest one, and the most sophisticated, that forms the foundation of the site is the same type as that at Sacsayhuaman. The next level is hardly comparable and presumably was added by the Incas. The last, and crudest, is a product of recent attempts at restoration.
The method of precise construction at Sacsayhuaman has yet to be replicated or explained. The method of transporting the huge stones to the site as well as lifting them into place is a complete mystery, as the proposed explanations (speculations) are ludicrous.