Kaluza-Klein vacuum multi-black holes in five-dimensions
  We investigate five-dimensional vacuum solutions which represent rotating multi-black holes in asymptotically Kaluza-Klein spacetimes. We show that multi-black holes rotate maximally along extra dimension, and stationary configurations in vacuum are achieved by the balance of the gravitational attraction force and repulsive force caused by the rotations of black holes. We also show that each black hole can have the different topology of the lens space in addition to the spherical topology, and mass of black holes are quantized by the size of extra dimension and horizon topology. 
Ken Matsuno, Hideki Ishihara, Masashi Kimura, Takamitsu Tatsuoka
hep-th gr-qc