Researchers are attempting to unearth how the Romans made cement so that they can reproduce what is apparently a much more durable, less polluting method and formula than modern concrete. This, to anyone who has gazed upon Roman ruins, aging beautifully over thousands of years, makes so much sense. Now, the challenge is for scientists to figure out just went into the Roman recipe for cement, and despite all our modern technology, there appears to be some disagreement on that score.