An old Polish man finds a magic bottle, and a genie pops out and offers him three wishes. The man thinks for a second and then says "I want Genghis Khan and his Mongol Horde to return from the grave and sack Warsaw, and then return home!" The genie agrees; undead warriors shall rise from the dust in Mongolia and make their way to Warsaw, raping and pillaging as they go, and when they reach the city the slaughter will be terrible.

The man thinks, and says "for my second wish, I want Genghis Khan to sack Krakow, then go back to Mongolia!" The genie says that this will happen; not one stone shall be left upon another, only pyramids of skulls will remain.

The man says "for my third wish, I want Genghis Khan to sack Lodz, and then return to Mongolia!"

The genie finally asks, "why do you want Genghis Khan to keep attacking your country?"

The man replies, "because he will pass through Russia SIX TIMES!"
http://timesonline.typepad.com/comment/2008/06/top-ten-communi.html