Ancient Artifacts Documented

These have more than likely been discussed before at least on an individual level but here is a site that lines up the top 10 unexplained artifacts. On the Alien view point some people are inclined to believe for example the pyramids were built by their technologies for special purposes; energy grounding, power plant, mapping, etc. But 1 out of the 10 artifacts discussed here are simply large perfect circular stones. What in the world would be the purposes of these? Not to mention they're found in such remote areas, debris? It would be nice to hear some theories to their purpose from an alien standpoint.

paranormal.about.com...

web.ku.edu...
A few of the stones are iffy, but I mean some of them are just so precise!

"Although the great stone balls are clearly man-made", I wish they
elaborated more on why it's so clear. From looking I beg to differ.

www.lonelyplanet.com... Who and what here would make these stones?

16 tons of mystery in my opinion!

[edit on 06/25/2008 by Sikmike620]

Very interesting artifacts indeed. Good find. Thanks!

Second line here