From what Margaret Curtis said it seems the local people still hold the the view that the stones at Callanish are the 'work of the devil' because they are pre-Christian. I have not done any research into whether this 'view' is actual fact or rather her long held perception. There is already an attractive low level stone-built visitors centre at Callanish (out of view of the stones) which also doubles as a restaurant for the many visitors who arrive in the summer so the 'work of the devil' theory doesn't really stand up. The visitors centre (and almost everywhere else) is closed on Sundays but inconvenience is minimal if you are aware of this before you go. I don't know how World Heritage status is obtained but imagine the elected councillors on Lewis might have to kick start the process. I would be interested to know.