International mobility of academics has risen over the last few decades, especially among PhD students and post-docs. This may be the result of deliberate policies to stimulate such mobility on the one hand and of growing imbalances in academic career opportunities on the other. The general belief that attracting international talents helps to ensure that a country plays a leading role in research and innovation, stimulates countries to develop initiatives to attract international students to doctoral programmes or to attract researchers who emigrated back to the country of origin. More traditional intercontinental mobility patterns from the south to the north and the east to the west, are now paralleled within Europe, where the disparities between countries in terms of R&D investment and skills shortages increase, related to the economic crisis. Consequently, brain circulation may easily turn into brain drain, and cultural diversity may decline. Related policy questions are whether this will unavoidably result in a (further) concentration of the minds in a limited number of regions or hubs and how this should be considered from the point of view of quality, competitiveness, diversity, and the future of the comprehensive research university in Europe.