“Ring World”. A gem of Larry Niven's work. The most unique artifact in the entire history of world SF - and, according to Larry Niven, the most amazing work of engineering art since Dante's Divine Comedy. An artificially created “hoop” around the distant sun is tens of meters thick, millions of kilometers wide and has a diameter - in a billion. “Hoop”, the inside of which can accommodate trillions of inhabitants. “Hoop”, which again and again becomes an “arena” for wars, expansions and incredible, exciting adventures.