"Timeline" looks at the chronological development of the world's culture and events starting from the Big Bang theory to the 21st century. It encompasses historical eras including the Stone Age, Roman and Byzantine empires, and the Islamic Golden Age, as well as "oft-neglected" civilizations such as the Norte Chico and the Indus Valley. The book also depicts the post–World War I period, and concludes with events such as the Fukushima nuclear disaster and the "Charlie Hebdo" shooting.