According to the Organization for the European Minorities there are 110 minority ethnic groups in Europe involved in conflicts and land claims with their respective governing majorities. That's EU only, not the rest of the world. To see a list of those go to
Society for Threatened Peoples website.
Contrary to how it appears on a political map, the world is not and cannot be nicely partitioned into contiguous regions (or "countries") such that each country contains people of only one particular ethnicity. You would either have to engineer mass population migrations or expulsions, or you would have to forget about contiguous regions and end up with literally millions of tiny exclaves and enclaves.
People are not machines. They need something to sustain them. By no means do they get this at work, they feel lost in this vast meaningless world of capital, just another cog in the machine, and they would be right. So naturally they seek meaning. Often they find meaning in the idea of the nation. It is no coincidence that a person with a immensely draining and alienating repetitive job, will tend to cling desperately to an idea of nationality, as they find meaning and comfort in it when there is no meaning in their work. The presence of nationalist ideas is an indication that some groups in society feel its real material interests are being frustrated by forces outside or even inside the nation. The idea of William Wallace as an exponent of democratic patriotism gives to a medieval man the mind and sensibilities of a later, modern age. Wallace never fought for an abstract “people” or even “nation”, but always in the name of a legitimate power of which he was but the temporary protector or “guardian”. He battled and died for John Balliol.
There never has been, and never can be, socialism in just one country. Socialism will be one world-wide community without national boundaries, a united humanity, sharing a world of common interests, would also share world administration. This is the socialist alternative to the way that capitalism divides the planet into rival states and sets people against each other. But this does not rule out local democracy. It is sometimes said that world administration would mean power of central control over local democracy and that the objective isto create a super-state. In fact a democratic system of decision-making would require that the basic unit of social organisation would be the local community. However, the nature of some of the problems we face and the many goods and services presently produced, such as raw materials, energy sources, agricultural products, world transport and communications, need production and distribution to be organised at a world level.
Socialism will be a co-operative world wide system. Nations and frontiers and governments will disappear. Groups of people may well preserve their languages and customs but this will have nothing to do with claiming territorial rights or sovereignty over pieces of the world surface. To move forward, the dispossessed majority across the world must now look beyond the artificial barriers of nation-states and regional blocs, to perceive a common identity and purpose.
Because political power in capitalism is organised on a territorial basis each socialist party has the task of seeking democratically to gain political power in the country where it operates. This however is merely an organisational convenience; there is only one socialist movement, of which the separate socialist organisations are constituent parts. When the socialist movement grows larger its activities will be fully co-ordinated through its world-wide organisation.
There is but one world and we exist as one people in need of each other and with the same basic needs. There is far more that unites us than can ever divide us along cultural, nationalistic or religious lines. Together we can create a civilisation worth living in, but before that happens we need the conscious cooperation of ordinary people across the world, united in one common cause — to create a world in which each person has free access to the benefits of civilisation, a world without borders or frontiers, social classes or leaders and a world in which production is at last freed from the artificial constraints of profit and used for the good of humanity — socialism. There is in reality only one world. It is high time we reclaimed it. In socialism there will be just a free world for a free people. It could be like that now, so why not do something about it ? The world is ours for the taking. So why not take it?
"...By creating the world market, big industry has already brought all the peoples of the Earth, and especially the civilized peoples, into such close relation with one another that none is independent of what happens to the others...It follows that the communist revolution will not merely be a national phenomenon but must take place simultaneously in all civilized countries – that is to say, at least in England, America, France, and Germany.... It is a universal revolution and will, accordingly, have a universal range...The nationalities of the peoples associating themselves in accordance with the principle of community will be compelled to mingle with each other as a result of this association and thereby to dissolve themselves, just as the various estate and class distinctions must disappear through the abolition of their basis, private property." Engels