Berge Meere und Giganten (Mountains Seas and Giants) is a 1924 science fiction novel by German author Alfred Döblin. Stylistically and structurally experimental, the novel follows the development of human society into the 27th century and depicts global-scale conflicts between future polities, technologies, and natural forces, culminating in the catastrophic harvesting of Iceland's volcanic energy in order to melt Greenland's ice cap. Among critics, Berge Meere und Giganten has the reputation of being a difficult and polarizing novel, and has not received nearly as much attention as Döblin's following novel, Berlin Alexanderplatz (1929).