Urban or built environment

The Miraflores Bicentennial Park has been built on the Malecón de la Reserva and the Quebrada de Armendáriz. It was inaugurated in June 2022 as one of the created projects within the framework of the commemorations of the 200 years of Independence celebrations (1). It is considered a new green lung of Lima (2), as it has a green area of 30,400 square metres and stands on one of the cliffs of the Costa Verde (1). It has a system of terraces that replicates the construction model of the Incas, which has made it possible to additionally reinforce the soil and the slopes with the use of retaining walls up to 10 metres high, with horizontal geogrids and vertical geocells (1, 2). It was structured on a stabilised slope in order to mitigate the risk of landslides (4), and an irrigation system was implemented to stabilise the soil (4).
This space was built as a biodiversity garden with more than 160,000 xerophilic coastal species with low water consumption, 300 trees and 80 palm trees. It also offers places for tourism, such as viewpoints and squares, where cultural events, open-air activities and rest areas are held (1). It also aims to connect aspects of landscape conservation, preservation of biodiversity in the city, and the construction of a cultural landscape in which human action is complementary and friendly to the natural environment (9). Finally, it seeks to contribute to the reduction of the municipality's carbon footprint by reducing the harmful effects of urban expansion on the Lima cliff ecosystem, such as deforestation, water pollution and loss of biodiversity (9).

In 2023, the municipality of Cagliari initiated a project to transform 50 school gardens into vibrant, multifunctional outdoor spaces that enhance education and recreation. Co-funded under an EU program, this initiative aims to create environments where students can learn and play outdoors, taking advantage of the city’s favorable climate. The gardens are being upgraded with new features, such as trees, educational vegetable plots, diverse plant species, playground equipment, and furniture, to provide versatile spaces for learning, sports, and play.
Automated irrigation systems are being installed in each garden, conserving water by adjusting based on soil humidity and detecting leaks. This technological upgrade ensures efficient maintenance of the green spaces.
Overall, the project seeks to enrich the educational experience by integrating nature into daily school life. It aims to promote students' physical and psychological well-being through more opportunities for outdoor learning and activities, fostering a connection with nature, and improving the overall quality of the school environment (Refs. 1, 2, 3, 4 & 5).

For a Forest in Your Neighborhood" is an afforestation campaign by the DDOR insurance group, launched in 2022 as part of their Environment, Society, and Governance (ESG) commitments (Ref. 1). Site selection was based on online votings, with thousands of votes being casted from 188 towns across Serbia (Ref. 2). In the end, the fifteen most popular cities were selected for project implementation. As a result, hundreds of trees were planted, including 25 trees along the promenade of Belgrade’s Ušće Park in 2023 (Ref. 3). Ultimately, the initiative aims to create and enhance urban green spaces, to improve air quality and living conditions in Serbian cities (Ref. 5). The success of the campaign encouraged DDOR to extend the campaign in 2024, financed through their eco-insurance schemes (Ref. 4)

Due to rapid urbanization and development, cities in China, including Kunming, face challenges in managing neglected urban spaces, particularly vacated demolition sites and leftover land (Ref 1, 2, 3). To address this issue and enhance residents' well-being, Kunming has created 400 pocket parks since 2022, transforming forgotten corners into vibrant green spaces (Ref 4, 5).
One of these parks, Wenxing Pocket Park in Xishan District, was built in 2023 on 2.3 hectares of land (Ref 6). Located next to a secondary school and two protected historical relics, the park not only preserves historical heritage but also reflects cultural value (Ref 6, 7). In addition to increasing urban green spaces, the park provides recreational and physical facilities for residents, children, and students (Ref 6). Its design is inspired by traditional architectural styles and incorporates wood craftsmanship, as well as ecological sponge facilities (Ref 6, 7).
The park also features science gardens, promoting awareness and knowledge of herbs and sustainability (Ref 6). The project employs methods such as infiltration, stagnation, storage, purification, and drainage to manage rainwater effectively. By utilizing the natural terrain, it creates ecological dry streams and sunken gardens that absorb and store rainwater, helping to control runoff. This approach aligns with the "sponge city" concept, promoting natural water accumulation, infiltration, and purification.
Additionally, the integration of various plants enhances the microclimate, supporting local wildlife and creating a healthy, vibrant public space. The Wenxing Pocket Park has been implemented by the Municipality of Xishan. (Ref.6,7)

The requalification project for Viale Buoncammino in Cagliari aims to revitalize the historic promenade while preserving its original layout and functions. Launched in September 2022 and completed in 2023, the project focused on enhancing the area’s aesthetic and environmental appeal. Key improvements include expanding green spaces by adding 560 new square meters, enhancing vegetation, and reducing surface runoff. This involves increasing permeable surfaces around existing trees to boost natural vegetation, improve bioclimatic comfort, and manage runoff during heavy rains.

The project also includes reconstructing pavements, optimizing seating areas, and repositioning urban furniture for better functionality and aesthetics. A modern LED lighting system will be installed to reduce energy consumption and operational costs, supporting the project's sustainability goals. The area is included between via Anfiteatro, viale Buoncammino and viale Giussani and also includes the squares F.Pilia and Marongiu-Pernis. The project aims to restore Viale Buoncammino as a dynamic social and cultural hub in Cagliari, appealing to both residents and visitors. (Refs. 1, 2, 3 & 4).

The Vera Park is a significant site in the city of Tbilisi, created in the mid-20th century. Located centrally, it is not only frequently visited by tourists but also used as a recreational area for the surrounding residents and workers (Ref. 1,2). The park is recognized as an immovable cultural heritage site, emphasizing its historical significance (Ref. 1). However, its condition had become quite desolate, necessitating extensive rehabilitation while preserving its original features (Ref. 2). Importantly, the project is carried out between the city of Tbilisi and the Asian Development Bank under the Livable Cities Investment Program (LCIP) to improve urban and tourism infrastructure (Ref. 1,2). As such, the project was developed through co-participatory planning, engaging citizens who have shown significant interest in the site’s development and will further serve as a precedent case for co-participatory planning in the future (Ref. 4,2).

The Urban Forestry Plan for Cartagena, led by EPA Cartagena, outlines a comprehensive strategy for enhancing the city's green infrastructure. The plan focuses on selecting suitable tree species, planting, and management to achieve several goals: reducing heat through shade, creating microclimates, protecting against climatic events such as coastal erosion and windstorms, enhancing food security, and enhancing the landscape's beauty. Over 10 years, the plan aims to establish at least 100,000 additional trees, increase overall tree cover, enhance accessibility to green spaces, and build a main ecological structure based on natural resources and biodiversity. It also emphasises the importance of local knowledge and resources (ref 1).
Formulated with community input, the plan commenced in 2013 and involved a detailed assessment of existing urban vegetation and climate conditions, utilising tools such as iTree. The development included international conferences and expert consultations to ensure a robust and informed approach (ref 1).

Liquid 3 is the first urban photo-bioreactor in Serbia, developed by an interdisciplinary team at the Institute for Multidisciplinary Research at the University of Belgrade (Ref. 1,2,3). Prompted by an appeal of the United Nations Development Programme (UNDP), the team was eager to find novel approaches to combat the city's severe air pollution issues while being space efficient and providing year-round benefits (Ref. 3). The key to the bioreactor are algae which are very efficient in sequestering carbon and filtering heavy metals from the air (Ref. 2). A Liquid 3 feature can be quickly set and occupies a plot of only 3 m². Some of its benefits include its ability to withstand high levels of air pollution and its ease of installation on surfaces like walkways and other sealed infrastructure (Ref. 2,3). Additionally, by design, Liquid 3 integrates amenities such as power outlets, a bench, and nighttime lighting (Ref. 1). The selected strain of algae can tolerate temperatures between 5-35°C making it deployable all year. However, monthly maintenance is required, during which the water and algae are replaced—both of which can be repurposed, for example, as fertilizers (Ref. 6).The project has received global media coverage as well as a prize for the best innovative and climate-smart solution in Serbia. Its success has prompted the installation of two more such bioreactors in Serbia, with interest coming from other countries such as Hungary and the UAE (Ref. 1,4).

In 2022, the municipality of Cagliari launched a project to revitalize Viale Trieste, one of its avenues, by redesigning its roads and pedestrian areas and adding new green spaces. The project covers approximately 1,300 meters and 36,500 square meters, and will be completed in two phases, each focusing on different sections of the avenue. With a budget of 12 million euros, funded by municipal, national, and EU resources, the aim is to transform Viale Trieste into a vibrant, accessible, and attractive space for everyone.

The renewal will introduce new green spaces and improved drainage systems to enhance soil permeability. As part of this, some trees will be relocated to other areas of the city to address root issues and improve survival rates. Dead or unstable ficus trees will be removed, while 79 new trees will be planted. Older ficus trees will be relocated to city parks, with younger ones planted along the avenue to prevent pavement damage and promote sustainability. The project also includes upgrading water supply and drainage systems to manage stormwater more effectively, reducing the risk of flooding and improving sustainability. Public lighting will be modernized, with new street lamps and dedicated lighting for pedestrian and bicycle paths to make the area safer and more welcoming after dark.

However, the community has expressed concerns about the project, citing safety issues, delays, disruptions, and poor communication from officials. There is also significant opposition to replacing the historic ficus trees, valued for their environmental and historical significance, with Chinese pear trees and younger ficus (Refs. 1, 2, 3, 4, 5, 6, 11, 16).

The Parque Lineal de Crespo in Cartagena, Colombia, is an urban green space built in 2016-2017 that had fallen into neglect (ref 4) and recently has undergone revitalization initiatives (ref 2). Announced in January 2024 by the Mayor of Cartagena, Dumek Turbay Paz, the project aims to reclaim and enhance this public park as a hub for recreation and community activities, fostering urban well-being and environmental stewardship​ (ref 2 and 3). The local government spearheads the intervention, and the Instituto Distrital de Deporte y Recreación (IDER) has been tasked with the park's management, ensuring its upkeep and the development of activities. The project was launched following an inspection by the Mayor and other local officials, who underscored the need for better infrastructure, safety, lighting, and green coverage through tree planting ​(ref 2 and 3). The primary objectives of the Parque Lineal de Crespo project include revitalising the park through enhanced maintenance, security, and the introduction of recreational and sports facilities. The project also aims to relocate weekend recreational activities, such as a popular bike path (ciclovía), from the congested Avenida Santander to the park, thereby reducing traffic disruptions and enhancing safety ​(ref 2 and 3). The park is relevant for the city because it combats coastal erosion caused by the rising Caribbean waters (Ref 1). The Park aims to be an icon of culture and recreation (ref 1). The project inspired a neighbours initiative, the Friends of the Crespo Linear Park, are a non-profit organization whose objective is to collaborate in the conservation of the Park by contributing awareness initiatives to the population, alerting authorities, and developing new ways to interact with the environment, such as guided bird watching activities and sports (ref 1).