I invite you to read about Pumapunku. This small archaeological site located near La Paz, Bolivia, contains some of the most astonishing ruins ever found. Massive interlocking stones weighing over 100 tons are found there. The site is said to be 17,000 years old. And yet, the stone carving and shaping is so precise that it cannot be matched with today's technology. If you haven't heard of Pumapunku, please read a bit. You will likely find it as fascinating as I do.
http://www.world-mysteries.com/mpl_6.htm
http://www.world-mysteries.com/mpl_6.htm