Secrets of Lost Empires

. Through Pharaoh's Obelisks and Easter Island's big statues, it attempts to explain how the ancient engineers could move and erect huge gigantic stones - weighing from tens of tons to hundreds of tons - with simple tools without today's powerful tools like crane. And then it, through the ancient Roman public bathhouse, attempts to reveal the ancient Roman building technology such as new building material we now call concrete, water distribution system and heating system. Finally, it takes us a journey of building a Rainbow bridge in a small village in China's Anhui Province, which tells the ancient China's bridge building technologies as well as why they developed Rainbow bridges.