The strength and longevity of Roman marine concrete is understood to benefit from a reaction of seawater with a mixture of volcanic ash and quicklime to create a rare crystal called tobermorite, which may resist fracturing. As seawater percolated within the tiny cracks in the Roman concrete, it reacted with phillipsite naturally found in ...
Any examples when one civilization/country got technology from another and after due to lack of knowledge lost it.
What about the United States and manned space flight?
How We Lost the Ability to Travel to the Moon
The United States space program was based upon the German WWII space technology.
The United States military ...
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I can think of a few examples:
In Egypt, I think the Low-Nile part, under Hyskos, obtained some horse vehicles but the Egyptians built them by themselves later
During the Middle Age, can't recall of specific examples but I am sure some technologies (especiallly farming technics) migrated from abbey to abbey without a continuous ...