Scientists Have Found the Ancient Secret of Indestructible Concrete

For the most part, we humans are better at things than we were thousands of years ago. But there are some things the ancients had down pat. Roman concrete, for instance, is just way better than anything we can whip up today. Finally, after some 2,000 years, modern-day scientists have figured it out. And it's a secret… » 6/15/13 5:30pm 6/15/13 5:30pm