Vatican City, February 17 - One of the greatest dangers facing the world is a "unity without differences", Pope Francis told students and staff at Rome's Roma Tre University Friday. "There is a risk of globalisation that fosters uniformity", he said. Rapid communication "does not prevent us saying No," the pontiff added, urging his listeners to "get used to dialogue at speed". The pope also said EU youth unemployment levels were "not fit for civilised countries" and that "perhaps not all the statistics on youth suicides are known". Europe was "born of migrants" but today the Mediterranean has become a "tomb" for too many desperate people seeking a better life, the pope said. He urged his listeners not to "fear migrations" since they were a "challenge for the growth of society". Francis told his audience that countries should "make peace and make investments" on migrants. The "ideal" solution for migrants, he said, was to "welcome and integrate" them.