Here is an interesting article by Gabino Ponce Herrero on the evolution of the urban planning context in Havana during the first half of the XXth century. It is also the story of the eastern urban extension project, first thought as a private development linked to the new tunnel under the bay, and later developed under the socialist regime in a different way. The economic evolution of the country has made of what was to be a model (and would today probably seem a common social housing project in most of Europe) just an isolated work.
Havana
Re-mid-sized cities (2) Ancient maps

New Orleans in 1718 as a project. A rather naive one, as the relative scale of things is quite unaccurate (the relation between the river and the Pontchartrain lake is an example).

New Orleans in 1744. Things have become more real (lots, buildings), the size of things is also more accurate
Re-mid-sized cities (1) A sample
- New Orleans (image on http://landsatlook.usgs.gov/)
- Havana (image on http://landsatlook.usgs.gov)
- Marseilles (image on http://landsatlook.usgs.gov/)
- Seville (image on http://landsatlook.usgs.gov/)
A mid-sized city can be such as a result of growth until reaching that status, or it can be the result of a certain downgrading from higher ranks. I am fully aware that some of the things I’m going to say could be unpleasant, but this is a long-term vision, and history is made every day, so nothing is unavoidable.
I’ve chosen four cities that, as in the first case, are seaports, but with quite different roles. They have been high places in the European colonial adventure (that could receive other names in different places). Seville as the main port in the first times of the Spanish empire, Marseilles as the French gate to the African and Asian empires, New Orleans as the gate to the Mississippi Valley, and Havana as the capital of the last jewel of the Spanish empire. These are by no means small cites, and they are rather relevant in their states, as to make many think that I’m not fair saying they are mid-sized cities; but they are no longer cities with a continental reach. They have sure gained population, but have lost rank.
Yet they are very interesting places. How does a city evolve when the technological- economical-social (you name the issue) wave that propelled it to its highest position disappears? The rise of these cities is linked to their network of relations in colonial worlds, and their evolution is related to the fact that new models appear that are more successful. There is a scent of Detroit here…
Biblio (29) Vedado, Havana
And now for a singular plan by many standards. El Vedado is a municipality in metropolitan Havana whose urban layout can be seen as an exemple of the innovative projects of the European urban planning tradition in the XIXth century; and I am fully aware of the fact that Havana is not an European city, but when the plan was aproved about 1860 (nearly about the same time of Cerda’s plan in Barcelona or Castro’s plan in Madrid) it was still a part of Spain, and the planning system is clearly different from the classical colonial grid. El Vedado is indeed a grid, but a different one, which as almost any other plan has been subject to modifications, maintaining despite that many values. I’ve never been to Havana, but the place seems to appear as often as an icon as the Barcelona ensanche appears in Spain, for instance.
It is not a scoop that Cuba has an unfrequent economic system; it is curious that, at least at first sight, the plan assumes a language about investors and development that seems not so different from what we would see overseas.
It is also surprising to see that this plan is organized and explained as a new urbanism document (even when the aproving organ is a people’s commitee). And it has received an honorable mention at the Driehaus Award of the Form Based Codes Institute, a US based organization.
All these are just special conditions. I repeat, I have never visited Cuba and so I have to judge by second hand sources, but the plan seems interesting in many aspects; across the Atlantic it would probably be subject to controversy due to the new towers along the waterfront, but across the Florida straits this woul probably be seen with no suspicion. The historical and analitical parts are well writen (and seem a good intro to the recent history of central Havana), and the bylaws seem coherent. There is a subjacent smell of the New Urbanism transect, and the hands of some Barcelona consultants is also aparent.
The document can be consulted at http://formbasedcodes.org/files/driehaus/ElVedadoMunicipalCode-2012Driehaus-reduced.pdf