The big Museums have the greatest advantage when it comes to the artefacts that the UNESCO heritage sites and others want back -- the big Museums have possession. Further, the Museums typically reside in the countries that made the laws governing repatriation. But as cultural tourism continues to be a growing and massive business, the UNESCO sites are making their own big Museums and are able to hire their own lawyers to defend their interests (check Zahi Hawass' Most Wanted List). The complex battle for who controls artefacts is really heating-up now. Perhaps the issue of who owns antiquity is possibly less urgent than who controls it.
