‘Urban regeneration’ seems to be the main strategy for the current city. Unlike a few decades ago, reviewing existing urban areas is not only focused on the historical areas but also the most recent ones. First peripheries of our cities have been demanding our attention for years, and they are incorporated in the urban agenda. In particular, residential districts are now considered not only for their antiquity but also for other urban deficiencies.

Urban regeneration channels in Europe, and particularly in Spain, the latest urban discussion forums. It is part of an integrated urban development context and it pretends to pay attention to the most vulnerable urban areas (Leipzig Charter, 2007). Right after a criticised expansionary period, many of the consolidated urban spaces demand our urgent attention. Those areas demonstrate a need for regeneration because of their deficits and the rooting of their urban communities.T

he criticism of previous urban growth model has lead debates, publications, legislative reforms and proposals that have kept this topic between the main urban matters. Varieties of contributions are making the effort to interpret contemporary urban processes and to classify the characteristics of the inherited spatial áreas.

Several attempts to clarify needs and degrees of interventions have been done, even pointing out the design criteria that should follow the proposed operations. Furthermore, efforts to identify areas that need to be regenerated have been made, from perspectives such as social vulnerability, building conditions or social and functional segregation.

The potential for transformation and improvement of the city is called into question by the discipline and it leads to an evolution of the policy framework.

Interventions tent to evolve into a generalized action in the built city, under criteria of sustainability, energy efficiency or social action in the most fragile environments. All this is accompanied by a review of other major issues, such as mobility, public space, distribution of functions, green infrastructure, housing and even a possible revival of the job market to this sector. After focusing on rehabilitation of historic areas and later in deprived residential neighbourhoods, urban regeneration still has to demonstrate the integrity of this new model.

All these elements provide the possibility of a new approach: from coordination of actions concerning recovering vulnerable urban areas, as well as management models in order to combine property rights with social rights, or mechanisms for assessing the suitability of proposals for an integrated planning strategy. Is it possible to draw a new line of regenerative action capable of guiding the entire city, a truly integrated one?

After the call for papers of this issue of Revista Ciudades, published works have provided different approaches to illustrate the current state. They provide keys to the analysis of the state of the art, in which different regeneration strategies have to be set in order to reach the theoretically planned objectives, reflect on the different scales of intervention and observe a variety of methodologies, management possibilities or financing ones.

Articles such as that of Agustín Hernández Aja and Ivan Rodríguez Suárez carry out a clear analysis of what has happened in recent decades, in terms of both real estate level and the way of approaching rehabilitation and urban regeneration. They highlight the keys to address the situation of vulnerable neighbourhoods, taking into account the benefits that an integrated urban regeneration can bring, being aware of the diversity of their possible interventions and the difficulties that arise. In this sense, the work of Víctor Pérez-Eguíluz, Miguel Fernández-Maroto and Enrique Rodrigo González is complementary. It explores conditions for regeneration that are deduced from the evolution of current regulations. They also defend the possibility of implementing a holistic perspective of actions, from urban planning but also from financial strategies aware of the need of optimizing resources through the quality of proposals.

Other works have shown the potential of urban intervention at various scales. Not without difficulties, planning is called to play an important strategic role in the regeneration of cities, developing new ways of working. This is explained by Irene Poli and Chiara Ravagnan through the experience on the 2008 General Regulatory Plan of Rome -with almost ten years of perspective-.

The intervention in fragments of cities also demands new methodologies and criteria to increase the potential of planning. Otherwise, it faces difficulties or overly partial visions of reality. This is evidenced by Gregorio Vázquez Justel from the figure of the Special Plan for historical centres, by Esteban de Manuel Jerez and José María López Medina from the research project ‘Barrios in transition’, or by Jorge León-Casero and Ana Ruiz-Varona after analysing Strategies of Sustainable Urban Development.

In some cases, necessity of intervention and excessive wait to which certain areas are subjected to, provoke the direct action of their inhabitants or neighbours on specific spaces. Publicly owned buildings and lots are often blocked due to lack of funds or due to their conditions of ownership and use. The text of Alicia Gómez Nieto explores formulas for these processes, whether temporary or integrated in a future planning. In addition, the paper of Franceso Gastaldi and Federico Camerin states, with a critical view, the conditions for public estate to be used to activate or accompany the processes of urban regeneration in Italy.

Funding is often an insurmountable obstacle, becoming a factor that can discriminate part of the affected inhabitants or it can distort the sense of the operation. Comparison of alternatives through new ways of obtaining resources and managing operations is explored in the article of Carlos J. Rosa Jiménez, María José Márquez Ballesteros and Daniel Rivas Carrillo, as well as in the work of Carlos Jiménez Romera, Patricia Molina Costa and Olatz Nicolás Buxens.

It seems not being enough applied territorial and comprehensive views of the problem of regeneration. There are some approaches to sectorial visions in this sense, although sometimes integrated vision of the territory is explained more by competency matters than seeing the obtained results. Rafael Temes explains this from the contemplation of mature tourist destinations, such as the Canary Islands. They are sets of spaces with territorial significance that demand regeneration interventions.

Altogether, this issue of Revista Ciudades has grouped several approaches: research programs and projects that aim to highlight the needs or the regenerative potential of different initiatives, analyses of capabilities and methods in the light of recent regulations and regeneration plans, and illustrative cases that allow us to value achievements and failures.

Debate is far from being closed and it will continue. It shows the difficulty both to generalize formulas and diagnoses or objectives. It sometimes leads to different results from those announced.

Valladolid, June 2017