What's a good introduction about lelin and stalin

Lenin believed in "pure communism" a lot like Karl Marx -the founder of communism- while Stalin was not. Stalin basically wanted to take over Russia -he was thought to be worse than Czar Nicolas- Stalin is believed to have murdered the Czar and also was bit of a '"rule-breaker" considering pure communism had no religion because it was false hope but Stalin allowed it to control the people. Stalin would murder people aginst communism and used the KGB to control people. Now back to Lenin, Lenin was aginst the war (the whole communism thing took off after WW1) and Lenin saw that after the war was a great time to carry on Marx's work (Marx passed away shortly after the war) Lenin was a great speaker and really knew how to "get the crowd going" .

Ifound this on google “the existence of agglomeration economies is central to the explanation of how cities increase in size and population, which places the phenomenon on a larger scale. the concentration of economic activity in cities is one reason for their development and growth.” i hope this you for what your looking for.