Archaeologists Mistook Numerous Concrete Objects for Natural Rocks.

Concrete Blocks on the Great Pyramid in Egypt:
[link to www.livescience.com]
[link to www.geopolymer.org]
[link to www.geopolymer.org]
Concrete Pavements on Mars:
[link to www.flickr.com (secure)]
Concrete Blocks on the Bosnian Pyramids:
[link to www.bosnianpyramids.org]
Concrete Pavement/Blocks at Göbekli Tepe, Turkey:
[link to www.flickr.com (secure)]
Concrete blocks off the Japanese coast (Yonaguni Monument):
[link to wretchfossil.blogspot.tw]
[link to wretchfossil.blogspot.tw]
Read more at [link to wretchfossil.blogspot.tw]