Here is a list of technologies, inventions knowledge and techniques that have been lost to time.
Some have been reproduced but only with the ability of modern technology tools and knowledge
Sometimes you wonder if humanity had not lost any knowledge over history how we would have developed
http://listverse . com/2009/07/31/top-10-amazing-lost-or-suppressed-inventions/
http://www . toptenz . net/top-10-lost-technologies . php
http://toptenworld . net/people/history/top-10-most-impressive-lost-technologies/10/
http://www . viralnova . com/lost-inventions/