How to expand a historical city?

Many cities throughout the world are looking for a viable strategy for growth. In many cases, the answer to "growth" is seen in "expansion": increasingly adding suburban areas to an already sprawling city. The looming problems are ominous: an increase in congestion of traffic, an increase of pollution, a longer distance (both absolute and relative) to a city's vital cultural and recreational functions, risks of segregation and gentrification... the list of potential woes of increased suburbanisation of cities goes on and on.

The solution is obvious: if one is able to increase the density of existing historical city centres, without losing life-quality in those inner-city cores, growth is contained within it's own structure. Thus allowing for a compact city, with smaller distances to travel, proximity to all the lures of the centre, and a more lively centre at that.
Strangely enough, in many cities the exact opposite effect can be seen. For instance, take a look at Rome: in 1951, about 357.000 inhabitants were living in the historical centre of this city. Nowadays, their numbers have dropped to about 100.000.
So whereas it might seem logical to densify (and intensify) the historical city in order to allow the city to grow, there is a big drop in number of inhabitants.

This was the point for the Italian architecture firm IaN+ to start their research project. A case study of the historical centre of Rome serves as an example of a wider phenomenon, which they called the "Re-living the Historic Center".

Their analysis of the reasons for the decrease of inhabitants in the centre is threefold:
1. The financial profit:
downtowns are exclusively transformed according to economic “needs”, seeking mainly the increase of property value; the residential emptying produces the disappearing of the neighborhood structures and dynamics that have always characterized the city's life and complexity.
2. Tourism:
the invasion by the “tourism machine” causes the replacement of residential use with accommodation facilities and the resulting eviction of residents. In various areas of the historic center the daily number of tourists is at least twice the number of inhabitants in the same areas. The tourist-oriented structures are becoming the prevalent program; the downtown commercial fabric, constituted by small businesses, is disappearing, to be replaced by large shopping malls in the outskirts of the city.
3. University:
in Rome there are three large public universities, and the same amount of private universities plus a series of specialized institutes. Since there is not a proper typological response to the student population, students are forced to look into the normal residential market, so that they often replace most of the residents who used to live around university campuses.

These three effects create urban tissues with holes in it. Not physical holes, but holes of practical use. The streets and the facades are important for mass tourism, some building blocks have strong economic value. But for many buildings, only the facade (the way they present themselves to the public) matters: the inside of the building has become out-of-use.

The solution they propose is as simple as it is radical: demolish the under-used buildings in the historical centre. But leave the facade, since this is an important part of the decor for the huge tourist-industry of the city. Behind this empty facade, the social structure of the neighborhoods can be strengthened, by inserting housing facilities in this recycled city structure.
Behind the facades, structures of housing and open space can co-exist, in order to create a second type of structure of the city: next to the tourist economy of the city, a system of inhabitants and ecology.


It might be a bit naive, it might be a bit too simplistic, and their architectual solution might not be the most convincing one: The idea of this project certainly has some fascinating points to it.
A fact is that an increasing number of historical city centres are falling prey to mass tourism. A fact is that there are less and less inhabitants in these historical centres. And a fact is that one needs to devote though to the reclaiming of the city centres to actual city life, and consider alternatives for the continuing de-densification of those centres.