How does a country attract talented migrants?

Even though someone might think that nowadays the USA has a negative policy towards migrants, or better to say immigrants coming to live in the States, the truth is - thanks to their politics and smart planning in the past, by importing "brains" from all over the world they had been able to develop all major industries and to flourished economically faster than any other country in the 19. and 20. century ( of course this is not the only reason). Let us just take into consideration that Albert Einstein, Nikola Tesla, Levi Strauss, Joseph Pulitzer were all immigrants and not to forget those who are still making the USA great like Sergey Brin ( Google), Arnold Schwarzenegger (actor), Mariano Rivera (athlete), Mila Kunis ( actress)... Anyhow, the list is very long and the previous comments indicated the obvious - offering good opportunities in the fields of education, research, work or sports career will inevitably attract creme de la creme of the society worldwide.