The 20th century irrevocably changed people's ideas about knowledge, space, time, space, psyche, society, progress and art. It was also a deeply strange era, in which it is not so easy to distinguish a seer from a madman, but without understanding it we are unlikely to be able to comprehend what is happening now. Historian and journalist John Higgs suggests looking at the past century from the point of view of the history of ideas and the gradual penetration of the concept of relativity into all spheres of life. Why did the age of discord and disunity end with universal networking? What can science fiction and pop culture tell us about his philosophy and psychology? How did scientists and artists, without talking together, arrive at the same images? And finally, what can we expect from the 21st century if the previous one was full of wars and tragedies?