If ever such a project would be of interest to Farsight, there are couple of sites, which clearly have many puzzling questions about their origins:
1. Baalbek - city in Lebanon, known for its ancient temple complex, which Romans have built upon.
Of particular interest is so called "trilithon" - a group of three horizontally lying giant stones, being part of an outer wall.
Each one of these stones is 19 metres long, 4.2 metres high, and 3.6 metres thick, and weighs around 800 tonnes.
A couple of these giant stones are still lying in a nearby quarry, left unfinished.
2. Puma Punku - a part of a large temple complex, located in western Bolivia. The largest of Pumapunku's stone blocks is 7.81 meters long, 5.17 meters wide, averages 1.07 meters thick, and is estimated to weigh about 131 tonnes. The site is also know for it's peculiar geometric stone design. The blocks were fit together like a puzzle, forming load-bearing joints without the use of mortar.
3. Saqqara Serapeum located in Egypt and is known for its large single piece solid granite boxes, weighing up to 70 tonnes each with perfect geometric shape. Official historians consider these boxes as a tombs for sacred bulls. But there are other theories, one of which states that it may have been containers for some kind of machinery.
4. Many sites in Peru, which are known for it's gigantic stones, seemingly fused toghether. Hakktopin already mentioned them in his post.
Who is originally responsible for erecting such structures? How it was done and for what purpose?
On many of these sites the stones clearly have markings of advanced tools used in processing and shaping. In case of Peru and Bolivia, the quarries used for the production of the stones are usually many tens of miles away from the constuction sites, so there is also a question of transporting such heavy and large stones over long distances in ancient times.