translation.en: This is what's really complicated, that there were people living in places like the Grand Canyon, cooperating with each other, or on the savannahs of Africa, or on the frozen shores of Alaska, and then some of these villages grew into the mighty cities of Babylon, and Rome, and Tenochtitlan.
translation.zh: 复杂的是 那些住在大峡谷这样的地方的人 彼此合作﹐或在非洲的撒哈拉沙漠 或在阿拉斯加的冰岸﹐和那些村庄 逐渐变成伟大城市像巴比伦﹐罗马 湖中之城提诺契特兰