I have a really simple way of counting visited WHS. I consider a site as visited when I have seen at least one monument or protected feature in the site intended as the core zone.

I have a pretty esoteric criteria, it basically comes down to if I 'feel' like I have visited a site, based mostly on my intention on the trip.
The only real problem with this come from Sites with multiple locations, can I count a site as visited if I have only visited one of seven towns inscribed? Again with this I just make up my own mind weather I have done the site justice.
A few weeks back I happened to bump into some of the senior members of English Heritage management in a pub in London and it seems that within the office they collect WHS as well and have a reasonably strict criteria for counting a site as visited, including having to see 75%+ of multiple inscriptions which although reasonable would make some sites almost impossible to tick off (Iberian rock art site is made up of 700+ sites)
Several times I have 'seen' sites without visiting them as I just caught a glance or had no idea what they were only later to find out that were important and I don't count these. I have put them into a pretty frustating list of 'nearly' visited sites

As far as I am concerned, I try to count exactly what I have seen. For example, I have just been to Sicily and the site "Late Baroque Towns of the Val di Noto (South-Eastern Sicily)" includes 8 cities. Since I have seen only 2 of these cities, I count only 0.25 (2/8). I plan to see the other cities the next time I go to Sicily.
It's true that the "Iberian rock art site" is a pretty difficult one: I have seen only 2 of the 467 sites that can be visited which means 0.043 ;-(
It makes it even more challenging that the 75%+ rule described by meltwaterfalls but it seems to me to be more fair.

Multiple location sites are really only a "special case" of many sites which cover more than a single building in that there are gaps between their defined boundaries. But a site with 6 separate locations and say, a town, with a number of streets and districts both raise the same question of how many of the locations/districts/streets/buildings "need" to have been seen. It surely depends on whether the other "locations" etc really "add" anything or whether they are just "more of the same". And even single buildings have "multiple rooms" – How many rooms does one have to "see" to see 100% of Versailles! And with Natural Sites the problem is worse – what about multiple trails, mountains, lakes etc etc.

And all sites have an "experiential" aspect to visiting them which varies according to a very wide range of factors which can add to or detract from the value of what you "see". What if I go to the Okapi reserve and don't see an Okapi - 0% or 100%??? What if it is raining and I don't get the great view of somewhere, or if a significant aspect is closed on the day I visit, or we are there with a particularly good guide, or my viewing experience is ruined by a great clamour of school kids as I was going round, or I had a bad headache....... etc etc in reductio ad absurdam!!

And even if I do "See" it - one man's "See" is another man's "Missed all the nuances and interesting bits....." For instance I fully accept that I am not good at "seeing" Gothic cathedrals – I walk round and think "well it's certainly big" and then move on. If only I could really appreciate them – I know others get far more out of them than I do!

For these sorts of reasons I don't favour the "mathematical approach" but prefer the "qualitative" which inevitably has to be "personal" and not comparable across individuals. So I count a site as "seen" if I "see" ANY part of it and get that "simple count" issue out of the way. Whether I count it in my mind as "seen" is another matter altogether as I then take into account the sort of factors mentioned above. If I want to go back again then perhaps I can't have fully "seen" it! (Idea - perhaps I should have a list of Sites "I want to go back to"!! But then I need to balance these against "Sites I haven't yet seen but want to"!) In any case there will be things I don't realise I "saw" until I get back and do a bit of study and discover the significance of something possibly quite minor. That is why prior study is a help to avoid the situation of getting home and discovering that you missed something significant- which means it can't fully be counted as "seen" in your mind! But then I don't know what I don't know and might be missing all sorts of things on that basis - and I change over time as well and "see" different things so perhaps the true answer is that no site can ever be ticked off as "seen"!

3 stories (Not WHS related but still apposite I think)
a. We had just "seen" our first Polar bear in Svalbard – a brownish white "object" at 3 miles through binoculars from our boat which must have been a bear as it seemed to be moving . We all sat round and discussed whether, if that was the only one we got on the trip, would we have "seen" Polar bear. Later we had an hour following by boat at 20 metres a mother and 2 cubs "doing" what Polar bears generally "do" – not a great deal but generally behaving quite "bearlike"! We were pretty pleased. That evening our guide showed us photos of a number of Polar Bears tearing the flesh off a whale – who had "seen" Polar Bear?
b. In the Amazon forest an American millionaire was trying to "see" 1000 bird species in a year – he had a professional guide with tapes of bird calls and played one near us – out came a Goeldi's Antbird. Within 30 seconds the bird had been ticked and the pair moved on to the next on their list. At the same place was a guy studying Ant birds for a year. Who was "seeing" them?
c. In a small and frankly, undistinguished, Vermont town I asked where was the best place round there to go to see the "Fall scenery" - I was going to give it about half an hour - I mean, how long can you spend looking at orange leaves! ... "Man you could burn up a whole life here and still not see everything" was the reply. I was put in my place!

I've had this issue in mind for some time now but I'm still not clear just how much I have to do to be able to claim, with a clear conscience, that I have
"seen" a site (I usually use the rather childish term "bagging" when I visit a site). It has particular relevance for me at the moment as I will shortly be walking about 120 kms of the Camino de Santiago in Spain. When I add this to the 160 kms I have already walked will I have bagged this site?
When visiting Multiple Location sites, I consider a site bagged when I have seen 50% +1 of those locations. Of course there are still cases where I visit all the multiple locations making up a site, just for the sheer pleasure of doing so, and, in one recent case, Vicenza and the Palladian villas, after seeing about 8 of the locations, I decided that I was merely repeating the same experience and so moved on. Philistine? Perhaps.
So, I suppose unless a better criterion comes along I'll continue with my 50%+1 in most cases and rely on a gut feeling on a few exceptional occasions.

Regarding the 9 sites not open to tourists, could we consider having visited the site if we touch the official UNESCO plaque near the site? These are not in the central zone but seeing things like this would allow a less strict approach to validate the visit of a site.

http://www.worldheritagesite.org/connection/Not+open+to+tourists

2 examples:

http://www.ledauphine.com/loisirs/2016/12/02/une-plaque-celebrant-l-inscription-de-la -grotte-ornee-du-pont-d-arc-dite-grotte-chauvet-pont-d-arc

https://www.tripadvisor.com/SavedPhotos-g1537819-i219975336-Iceland.html

My criteria for a minimal visit is to take one representative photo of the site.

That is why I don't count a few places I've technically been to.

Although I'm quite a fan of unesco plaques, I wouldn't necessarily count a plaque as visiting a whs - the aldabra plaque is in vallee de mai, Seychelles but it would take much more effort (and money) to visit the former!

Ok, good arguments

The UNESCO plaque means nothing. You can stand on the sidewalk in front of the Stoclet House and see its architecture pretty well. Of course going inside would be "better", but I would not hesitate to count this.


That is a more difficult dilemma. If I were to visit again now, I would definitely aim for the protected area. I did count my previous visit to the wider region, but have it still in my mind to replace it with a "proper" visit.

It makes me think of when I saw Surtsey from a distance, I touched the plaque that is in this place, from Heimaey:
63.412837, -20.288353
I didn't go to the central area, even the maritime part. So I didn't count this site as visited.

Otherwise, concerning the Chauvet cave, I think touching the armored door of the original site and visiting the replica is a good visit.

As much as I like being on the lookout for UNESCO plaques, by no means would I count a visit based solely on finding them (most are changed or added after a while anyway). It's just an extra treasure-hunt fun. Personally, I count a site as visited if through my visit I manage to appreciate its OUV or sincerely try hard to appreciate it during my visit (after having done prior reading and post-research). My favourite part is actually being able to compare between visited and unvisted sites.

I was also reasoning about this issue as of late. I think I am more on the side of meltwaterfalls. But I also often indulge in considerations like those of Solivagant...

Indeed, very often I have to quench some kinds of personal perfectionist tendencies, following which I couldn't count any site visited if I didn't look in every corner and under every stone and graduated in a specialised course about the subject. This steers very much towards a "quantitative" experience. Of course I am exaggerating (... a bit), but in time, to preserve my mental sanity, I tried to let a qualitative, experiential "satisfaction" prevail, which from time to time has to deal with "partial sightings". And in view of what has been said before in the discussion, beyond some very minimal requirements (like at least seeing Surtsey to count it), I think that this is the only feasible possible approach, acknowledging that everybody will have its own experience...

A correlated question is: how do you consider WHS sites you visited in your childhood or early youth? For example, I count Siena even if the last time I went there I was 10 at most (it was in the previous century). But even if the present Astraftis (especially when not made reasonable by his girlfriend) would be much more meticulous in visiting all buildings and museums, I still keep a strong impression of the historical center, the place, the tower, the alleys... so yes, I know I "got" Siena. The same applies to Amsterdam, for which my memories are even more tenuous (I was 6, my first trip abroad!), but I can remember the canal, the boats, the brick houses, a sunny summer day, the wonder of everything being so different... Of course this was a totally different impression of what I would get now in a more "mature" visit (I hope soon). I could well count it twice, in a sense. All in all, knowing that the perception of a child is so much different than that of an adult (isn't it?), I count the sites that I remember significantly even if I would gladly return to some, and even if, rigorously speaking, the visit was "incomplete" (whatever this means).

Currently, I have to deal with different "problems". I always come back from a trip with a backlog of what I missed, either directly because of my planning or because of one of infinite imponderabilities: a museum that was closed, a peak that couldn't be reached because of bad weather, utter lack of time (well, this is somewhat ponderable...)... but in the end, did this really impair my enjoyment of a site? 90% of times the answer is "no". I was there, I lived it, I have memories, I count it. And I am finding that more often than not just studying the accurate motivations for the inscription of a site alone helps unlock a much greater awareness, as it does some information gathering afterwards.
For example:
* in Třebíč I couldn't make a visit inside the houses of the Jewish quarter because it cannot be booked by a single person, but apart from taking another guided tour I even overnighted in the quarter, so I cannot say I did not experience it (the backlog says: go back with someone else and book the "architectural" visit);
* in Bursa the encroaching boredness of my travel companions made us skip the most traditional neighbourhoods, but we did visit one of the key points, the mosque and some tombs (the backlog says: go back and take a walk through the Ottoman neighbourhoods)
* During my visit of Mtskheta, I didn't manage to visit the Samtavro monastery, unfortunately (and so the backlog complains).
And so on...

As for serial sites, I am undecided... here on the site we have to take a binary decision, but I like the approach of the World Heritage app for smartphone and tablets (probably many of you know it already): there I can tick out the single locations, and there is the difference between the green, "completely ticked out" sites and the yellow "partially ticked out" ones. This suffices to make me content: I can enjoy a kind of personal recognition. This is probably relevant for those more "homogeneous" serial sites like the enigmatic pile dwellings, but there are a lot which are quite unbalanced, and then I have no problems in counting one if I experienced the coremost zone. An example where I was recently are the Palladian villas: I think everybody could be content with visiting the center of Vicenza and maybe the Rotonda. Of course, visiting villas in the countryside never hurts and helps get a better understanding, but (meant in a very good sense) it is in most cases "just more of the same".

Finally, in some cases I am stricter. For example, I cannot count Genova, even if I have been there quite a few times. The fact is that I visited most of the historical and less historical center (and of course the Aquarium, the foremost reason for internal tourism), but never really walked down the precise streets of the WHS, nor visited its palaces. And since this is the whole point of that WHS, I cannot count it. And in a way I like it: this nomination wants to give me awareness about a very particular fact and prompts me to focus on it! So for next time I am prepared!

carmendavid
I think that our memory always plays tricks to some extent. But at the same time, this reveals what really has impressed us, be it majestic or trivial. In my memories, I notice that most things are disproportionated: streets are always longer or narrower, buildings smaller or greater, the light darker or brighter and so on, and sometimes yes, colors can "change". Other times the visual part has mostly gone and what remains are just abstract forms or other generic feelings. This does does not bother me too much: it still a way we process our experiences, so, if these sensations are vivid enough, I would "count them as visited" :-) Of course, a bare minimum of visiting the place is always a "requirement", but the degree varies with some factors (like age).