I thought it might be worthwhile exploring some of the suggestions found in the comments to Els's recent blog and see if we could prove or disprove any of them.

We had:

Tower of London/Westminster: from each other or Greenwich - could find nothing on photos taken from these three on the web.

Florence from Medici Villas (Fiesole) - The Duomo is visible in the first picture taken in the garden of Villa Fiesole:
https://www.gardenvisit.com/gardens/villa_medici_fiesole_garden

Fuji from Meiji sites (Nirayama) - not completely sure about it, but see second picture:
http://mineo.i-ra.jp/e757385.html

Saloum from Kunta Kinteh?

Persian Garden (Dowlat Abad) from Yazd
alternatively: Persian Garden (Chehel Sotun) from Meidan Emam
I thought this was reported by some community members. Any photos?

Tallinn from Suomenlinna

There is no doubt that Nirayama is recognised as "a" place to go to view Fuji - "Nirayama sees many visitors from bigger cities (such as Tokyo) coming for seasonal picking and the picturesque views of Mount Fuji." (wiki)
Yesterday I "did" a Google Street Map "tour" of the Furnace area and there seems to me no way that one can see Fuji from inside the core area. This is quite limited and the photo provided in the link will be outside it I believe up a hillside. The core area is surrounded by trees and buildings

Have a "go" yourself!!! https://www.google.co.uk/maps/@35.0396962,138.9621406,2a,75y,285.49h,92.73t/data=!3m6 !1e1!3m4!1sdiKwdLHDvetFguhUAqPkew!2e0!7i13312!8i6656

Re Fort Bullen and Saloum - A fuller calculation for what might be possible to see in "perfect" conditions can be done using this web site
http://www.ringbell.co.uk/info/hdist.htm
I think we can assume that Saloum is at or hardly above sea level.
If we assume that Fort Bullen is 14m above sea level and that the viewer is another 1.7m higher still - then the maximum distance which could be seen purely on the basis of the curvature of the Earth is 14.7kms. Google Maps puts the straight line distance between Fort Bullen and the tip of Saloum at 12.3kms. I would think that the other way round might be better - ie. making out Fort Bullen from Saloum. But in all honesty I don't think either is likely in the humid atmosphere of Banjul/Saloum. We have already tried to make the "Rules" for this Connection reflect "real possibilities" (I made the original suggestion and "rules" for this "Connection" having been to Tenerife and realising the possibility) - perhaps we need to extend them to cover for "Normal viewing conditions." I.e not a "once in a year" clear day using a Swarovski telescope and managing to see the flag flying at the top of the pole!!! Also exclude abnormal atmospheric conditions, reflection, refraction etc - "interesting" though they may be as phenomena!

Re Tallin From Suomenlinna
I don't know if people remember back in 2013 we had a discussion on whether it was possible to "see" Mt Etna (then erupting) from Malta 200kms away!!!
https://www.worldheritagesite.org/forums/index.php?action=vthread&forum=8&topic=1775
The accompanying links mention the effects of Refraction. The above calculator arrives at a distance of 206.7kms as the furthest distance where someone at see level could see the very top of a mountain 3350m high. I think also in the case of eruptions etc there will be "reflection" down from clouds/atmospheric dust etc. In the case of Tallin I suspect that what people on Suomenlinna are seeing is the reflection of Talinn's lights. The Google distance from Talinn t to Suomenlinna is c79 kms. Pikk Hermann (the highest tower in Talinn) is 45.6m. Even allowing for being on Suomenlinna at say 27m (the height of the Church tower that is a max distance of 27 + 45.6 m = 72.6m. A max distance to see of 30.4 kms. There seems no way that a direct image of ether place from the other is possible.

I have asked our guide from Iran about
Maidan Emam from Chetel Sotoun
Chetel Sotoun from Maidan Emam (specifically from the Ali Qapu)
Maidan Emam from Masjed-e Jame (available to tourists rather than Muezzins!!).
Juha Sjoeblom says he has photos which show Chetel Sotoun from Ali Qapu. It would be very helpful if he would send one to Els!!! I have checked my photos but none of them show it. But that may because I didn't take any looking "round the corner" AWAY from the Maidan and behind the Ali Qapu. Another possibility which occurs to me from remembering our visit is that the stairs to climb the Ali Qapu might have had windows at the rear of the palace which allowed views in the direction of Chetel Sotoun.
I supsect that the answer to the other 2 is negative. The Chetel Sotoun is surrounded by lush trees and all my photos would indicate that there is no real view outside it from inside.

Tower of London/Westminster: from each other or Greenwich
There is no reason to think that any of these is possible. As meltwaterfalls says - the Tower of London in particular is rather small particularly in relation to what has been built around it - much to the chagrin of ICOMOS!! The Thames does a lot of twisting as well so there is a lot of "London" in between any 2 places along it!

Nevertheless Els's raising of this issue HAS identified some additional connected sites which we had missed!

I have two photos taken from the backside of the tower of Ali Qapu away from Meidan. Chehel Sotun garden is not far away and you can see lush trees inside the inscribed area. Currently I'm spending weekend in orienteering competition so I'm not at my computer. I'll send the photos to Els when I'm back at home.

About Suomenlinna to Tallinn, I wouldn't accept this one because I don't think it is possible to see the old town itself. Maybe it is possible to see the television tower or the lights of Tallinn.

Just for reference, it may be helpful to include a couple of links for this thread.

First, the link to Els' original blog entry.

Second, the link to the Viewable from another WHS connection.

As Els mentioned in her blog, this connection excludes WHS that are contiguous or that are inscribed twice, and viewable should be under normal conditions for a tourist.

Thanks for your input, Solivagant. It makes sense that the haze and humidity might make the Saloum delta hard to see from Fort Burren (and vice versa). I agree with your assessment of Fuji-san from the Nirayama Reverbatory Furnaces; I'd made the same assessment after researching it earlier this week. The trees and low hills near the blast furnace appear to obscure Fuji-san at ground level.

I do have a possible new connection, though, which I will have to confirm later this year (unless someone else already has confirmation). On a clear day, the mountains of Waterton-Glacier International Peace Park should be visible on the horizon from the viewing platform atop Head-Smashed-In Buffalo Jump in Alberta, Canada.

Not from the top of the viewing platform but here is Google Street view from the road below it on a reasonably clear day - showing snow capped mountains oriented slightly west of due south i.e the correct direction for Waterton Lakes NP!!!
https://www.google.co.uk/maps/@49.7052306,-113.6532477,2a,15y,200.48h,90.57t/data=!3m 7!1e1!3m5!1sDLGGkN_jSy2_rrs2S8iBgg!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3DDLGGkN _jSy2_rrs2S8iBgg%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%2 6w%3D203%26h%3D100%26yaw%3D118.49828%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656

Confirm orientation with this and right click on the 2 points for the "straight line" distance c72kms
https://www.google.co.uk/maps/dir/Waterton+Lakes+National+Park,+Alberta+5,+Waterton+P ark,+AB+T0K+2M0,+Canada/Head-Smashed-In+Buffalo+Jump+World+Heritage+Site,+Fort+MacLeo d,+AB+T0L+0Z0,+Canada/@49.2597388,-114.2950301,9z/data=!4m14!4m13!1m5!1m1!1s0x536f431 18b9149bf:0xdf601e775403581c!2m2!1d-113.9166667!2d49.0833333!1m5!1m1!1s0x536e4d8d873b 72e9:0xcf88e7148552bb4b!2m2!1d-113.65342!2d49.705334!3e0

That works, Solivagant -- thanks! I feel like I'm spoiling a future visit to Head-Smashed-In Buffalo Jump by looking at the Street View, but it's good to know the range is visible (which it had seemed it should be from the ground photography I'd seen).

One more connection I found: Kangchenjunga peak in Kangchendzonga National Park is visible from the Batasia loop on the Darjeeling Himalayan Railway, one of the Mountain Railways of India.

Hmm. This should show all of your reactions too. Another thing to do on our technical backlog....

The Changdeokgung Palace is literally across the street from the back wall of the Jongmyo Shrine in Seoul.

Are these sites contiguous?

No, they are not. Jongmyo is angled in a way that makes contiguous views impossible. The foliage is also dense blocking any potential views within either site.

We currently have them "connected" as "contiguous" (in which case of course the "rules" don't allow a "viewable from" Connection as well) but it could well be, as GaryArndt says, that they are simply "across the street" from each other - i.e there is an uninscribed road BETWEEN THEM - Yulgok-ro!! Only Jongmyo has a site map on the UNESCO web site and its boundaries do not include Yulgok-ro. It would seem unlikely that it is included in the Changdeokgung boundaries if we had a map!
So it looks as if we
a. Should remove Jongmyo and Changdeokgung from the "Contiguous" Connection (We currently state "Contiguous National Sites: Changdeokgung Palace and Jongmyo Shrine are abutting sites" - it doesn't seem that they are!) - or we alter our definition of "contiguity" to include "close proximity" (how "close"?) as well as "contact" of boundaries?
b. Need to consider if they meet the "Viewable from another WHS" Connection. The question here is what constitutes "viewing" a WHS. Clearly one needs to be INSIDE the boundaries of the "from" WHS - not in the street outside. If one is inside site A and can see the trees in site B across the street and behind a high wall (or 2 "high walls" if site A also has a high wall between it and the uninscribed street) - does that constitute "Viewable"?? There are hills inside Changdeokgung - can anything be "viewed" of Jongmyo from them - even if only trees?

I can confirm to you that at Nirayama site itself, you cannot see Mt. Fuji, but if you walk to nearby tea plantation on the hill, then there is a spot that you can see both Mt Fuji and Nirayama.

He did, and he is right I think.

He is - not that we "doubted" it but it is nice to "understand" and share in the view we are "connecting" and to have a confirmatory record!
The Chetel Sotoun gardens are indeed those shown on Juha's photo surrounded by red. N.B. ONLY the green trees behind the tower under the blue circle- not the leafless ones in front. The Chetel Sotoun itself would be on an orientation just to the left of the dome in the furthest distance and is not visible - it has a low roof at around or below tree line