The Marmot's Hole has a link to newsweek's recent ranking of the world's universities. The Marmot points out that there are no Korean universities there, which is true, but I think more than that what should be clear is the overwhelming dominance of certain countries and one language as can be seen from my summary table below:
Number in Top 100
Number in Top 20
Obvviously the US leads with 44 of the top 100 and 15 of the top 20, but the UK is clearly in second place with 14 of the top 100 and 2 of the top 20. Not only that the top English university (Cambridge) is ranked 6th, with the next country's top university (Japan) coming in at 16.
The top four nations are all English speaking (even though Canada is bilingual, all the universities listed including McGill University are English speaking) and account for 70 of the top 100 and 19 of the top 20. If you include the former English colonies of Singapore and Hong Kong then 75 of the top 100 are "Anglosphere".
Conspicuous by their absence are (in no particular order) non Anglospheric Asian nations apart from Japan, Spanish speaking countries, slavic nations, the Muslim world and Africa. Even within continental Europe there are interesting trends, with two smaller nations punching far above their weight - Switzerland and Holland.
I am somewhat sceptical of the methodology since I would have expected some Chinese and Indian universities somewhere as well as perhaps a Finnish University (HUT) and a couple of Russian ones, but I don't think anyone would argue with the general conclusions.