Abstract: A rotor 16 is provided, comprising a vertical rotation axis 12, and at least two rotor blades 18, 20, 22 arranged on the rotation axis 12, wherein at least one rotor blade 18, 20, 22 comprises a curved first portion 40, wherein the first portion 40 has a concave side 42 and a convex side 44, wherein a curved second portion 50 is arranged on the end 46 of the first portion 40 of the rotor blade 18, 20, 22 facing away from the rotation axis 12. The second portion 50 has a concave side 52 and a convex side 54, and the two portions 40, 50 are arranged in such a manner that, in the radial direction, the convex side 44 of the first portion 40 is followed by the concave side 52 of the second portion 50. Due to the design of the rotor blade 18, 20, 22, the rotor 16 has particularly high efficiency.