I'm not sure whether the discussion on the Top 50 Missing is already over, but here's my two cents for the discussion:

- There's some I'd definitely give my vote to on the existing list: Bhutanese dzongs, Bagan, Shwedagon Pagoda, Panama Canal, Amsterdam, Nan Madol, Cape Canaveral/Baikonour, Tana Toraja, Meroe, to list just a few... as well as the La Brea Tar Pit in Trinidad and Tobago - never heard of that one before!

- A few other proposals from my side (sorry for not providing detailled criteria - it's getting late):

Full name of site: Birth of the skyscraper: Chicago, St Louis and New York
Country: USA
Short description of site (also include multiple locations if applicable): Historical skyscrapers of Chicago (Auditorium Building, Marquette Building and other 19th century skyscrapers), St Louis (Wainwright Building) and New York (Woolworth, Chrysler and Empire State Building; Flatiron Building)
Criteria (cultural, natural, mixed): C
Outstanding universal value / comparative analysis: Given the ubiquity of skyscrapers nowadays, I find it astonishing that none has yet found its way into the WHS.

Full name of site: Art Deco Historic District of Miami Beach
Country: USA
Short description of site (also include multiple locations if applicable):
Criteria (cultural, natural, mixed): C
Outstanding universal value / comparative analysis: The world's biggest concentration of Art Deco buildings, built during the first tourist boom to Florida in the 20's-40's.

Additionally, I would also support Asmara, which would have the additional benefit of being the first site in Eritrea and first African site to celebrate Modern architecture.

Full name of site: Synagogue of Subotica
Country: Serbia
Short description of site (also include multiple locations if applicable): Art Nouveau Synagogue in Subotica (on the border with Hungary)
Criteria (cultural, natural, mixed): Cultural
Outstanding universal value / comparative analysis: One of the best surviving pieces of religious Art Nouveau architecture; also, it would be the first synagogue to be listed on its own.

Full name of site: Forts of Rajasthan
Country: India
Short description of site (also include multiple locations if applicable): Multiple sites in Rajasthan such as Jaisalmer, Jodhpur, Amber Fort, and many more)
Criteria (cultural, natural, mixed): Cultural
Outstanding universal value / comparative analysis: Some of the most spectacular buildings of India. Fusion between Mughal architecture with pre-Islamic Indian elements.

Full name of site: Crystal Caves of Naica Mine
Country: Mexico
Short description of site (also include multiple locations if applicable): Caves with biggest natural crystals ever found, located 300 m below the surface
Criteria (cultural, natural, mixed): Natural
Outstanding universal value / comparative analysis: Unique geological site.

Full name of site: Babylon
Country: Iraq
Is on Iraq's Tentative List, but this city is so legendary that it cannot be outside the Top 50 Missing :-).

Furthermore, on the respective Tentative List: Marib (Yemen - Capital of the Queen of Saba), Plain of Jars (Laos)

Welcome aboard Khuft! We are always looking for new ideas, insights and experiences re WHS.
The Top 50 Missing certainly isn't closed - One day Els will be able to take some time off from travelling to set up a proper list and voting mechanism - given the way it evolved it is a bit difficult to follow all the earlier suggestions and comments!

Re your suggestions - the Miami South Beach Art Deco area has been proposed
http://www.worldheritagesite.org/forums/index.php?action=vthread&forum=6&topic=39
but certainly doesn't appear in the Index.

US skyscrapers also got a mention
http://www.worldheritagesite.org/forums/index.php?action=vthread&forum=6&topic=31
but perhaps without any great conclusion!

You seem to be a supporter of the "serial site" school Khuft. We have had debates about this. My view is that unless there is a VERY good reason for doing so such "serial lists" are "a bit of a cop out" and just reflect an unwillingess to differentiate - which of the "Forts of Rajasthan" and the "Skyscrapers of USA" are really of Universal Value and World Class?

Thanks for your comments and for the links to the previous discussions!
I fully agree that there should be an Art Deco WHS, and Miami Beach is the best choice in that case IMO.

I must confess I do favour a "broader" WHL - I'm a fan of architecture and actually do not mind that the WHL includes so many Gothic cathedrals :-). If e.g. Provins has been accepted as WHS, any town as exceptional as Provins should have the possibility of claiming the same title. Also, I'm looking forward to the next "ethnic" villages to follow Vlkolinec, Hollokö or Holsavice into the WHL. But I guess everyone has his/her own preferences about what the WHL should look like

Anyway - for the Forts of Rajasthan, I can't honestly say which one would be the most relevant. I'd have to look into more details about the individual forts.

On the skyscrapers - I do believe there should be a WHS with skyscrapers on the list, but in case you don't like serial nature of my initial proposition, what about these alternatives:
- City of New York (if Amsterdam was the commercial capital of the 17th century, New York was certainly the capital of the 20th).
- Chrysler Building (the most emblematic NY skyscraper which the additional advantage of being an Art Deco building).

Babylon suffers from some authenticity problems. In 1995, Saddam Hussein started rebuilding them and inscribed his name on many of the bricks. though undoubtedly one of the most significant places in world history, the actual ruins have some hurdles to clear before inscription becomes possible.
The Crystal Caves look amazing, a very worthwhile choice.
Personally, i don't support the inscription of single buildings (unless they are extremely important: like Sydney Opera House) so I'm afraid the Serbian Synagogue doesn't go down to well with me. If it were part of a broader proposal (such as art nouveau, or Balkan synagogues) i believe it would improve.

I wonder how polarized the forum is on the "serial site" issue. Solivagant has started a few threads which try to address the difficult problems of what is universal value, what is value of a world heritage list and what makes a good site but we (the forum) seem reluctant to discuss them. Are these issues too difficult?

I read about that too, and have two comments:
- in general, for my taste the authenticity dogma is sometimes used in too draconian a way.
- but in cases like Babylon, it is a justified question. The best solution would be to revert the work by Saddam Hussein, but that would probably be too expensive. So some middle ground has to be found.

Babylon will not be the only site facing authenticity problems. In Bagan, the Myanmar junta has been rebuilding temples and pagodas without any historical considerations. [This is apparently a general tendency for the junta; in Mandalay, they supposedly reconstructed an old palace by simply copying an existing building from another Burmese city].
In Knossos too the question of authenticity could be raised - but maybe Knossos can squeeze through the same way Warsaw did: not as a testimony to Minoan culture, but as a testimony to early archaeological reconstruction efforts.