By Adrian Masters - political editor ITV Wales
Wales has never seen anything like it - people living in Newport and Cardiff have become used to the almost constant drone of helicopters flying low over the tops of houses and armed police mingling with city centre shoppers.
Seven warships are moving into Cardiff Bay and protesters from across the UK and from all over the world have moved into a park on the outskirts Newport and set up their peace camp there.
Cardiff Castle, where the Nato leaders will enjoy their summit dinner on Thursday, has become doubly fortified: its ramparts now surrounded by a twenty-foot high fence which slices through a busy city centre.
In Newport, similar fencing surrounds the Celtic Manor Resort, the five-star golfing destination which is the summit's main venue. Not just there either: the fence extends for miles along the dual carriageway into the Usk Valley, enclosing hillside and woodland areas.
Yellow signs warn drivers that the main road into Newport will be closed for an expected demonstration on Thursday.
And around 160 schools are closed for part or all of the time the summit is being held.
Apart that is from whichever school it is that President Obama will visit.
If Nato itself divides opinion as the presence of protesters testifies, then the impact of holding the organisation's biennial summit has similarly divided opinion here in Wales.
There have been plenty of people willing to criticise the inconvenience caused by closing roads and schools, the appearance of so many police officers and the cost of staging such a huge event.
But there are also signs of people beginning to enjoy the excitement. Social media is full of pictures of the fences, helicopters and police officers and not all of it critical. Some are even playing Police Force bingo, ticking off the different forces which make up the 9,500-strong presence in South East Wales.
And I think a good-natured protest last weekend and the light-touch policing of it set many minds at rest about the risk from violent clashes such as those seen at the Chicago summit two years ago.
Many, including the Welsh Government, see the summit as an opportunity to showcase Wales and all that it offers.
Two giant tables for the leaders to sit around have been made locally using Welsh materials. Local food businesses have been invited into the summit to demonstrate the culinary range on offer nearby. And the Prince of Wales will host a reception for Welsh businesses.
And if it is being seen as a boost for Wales, that's even more true for Newport, my home city and one that has struggled in recent decades in the shadow of its bigger neighbour Cardiff. But it's also somewhere that has a long and proud history that encompasses medieval ships, the Chartist rising, music, photography and film.
There's been concern that Newport was being ignored: the summit's title doesn't feature the city's name as previous summits in Lisbon and Chicago did and some media coverage referred to it as 'the Cardiff summit.'
There's a growing realisation that, for all the inconvenience, the prospect of 60 world leaders and thousands of international journalists and observers may well make a difference.
I spoke to a prominent figure from Birmingham recently who told me that hosting the G8 summit there in 1998 marked a turning point in confidence and recovery.
The Prime Minister himself told me that the goody bags given to Nato delegates this week will make sure they leave with permanent reminders of the place they've just spent two or three intense days.
International events and the threat of terrorism at home and abroad have already seen this summit described as likely to be historic.
Its decisions will certainly be hugely significant to the world. But its presence will be hugely significant to Wales too.