简介：Historian Michael Wood's documentary series travels the globe to trace the origins of the tools and lifestyles that led to organized civilization. Wood visits the sites of the world's first cities, as well as early empires such as India and Chin
简介：科学家们利用DNA技术证明所有的人类拥有共同的祖先，为此他们来到人类的摇篮——东非。Scientists use the DNA from a random group of people to show that all humans share common ancestors. On a single day on a single street, with the DNA of just a couple of hundred random people, National Geographic