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The regreening project is located in Seestadt Aspern, a newly developed urban area in Vienna's Donaustadt district. Two years after the completion of buildings, streets, and squares, the ground was reopened in 2022 to address the challenges posed by urban heat islands. Pavement was removed, and trees and shrubs were planted to provide shade, create insect habitats, and open seepage areas for rainwater. Additional features like benches, a water station, and water jets were installed to enhance the area's livability. These measures improve the overall quality of life, offering residents green spaces to relax and opportunities to cool down through water play.
The project spans three connecting squares in Seestadt: Wangari Maathai Square, Simone de Beauvoir Square, and Eva Maria Mazzucco Square. In 2022, Wangari-Maathai-Platz and Simone-de-Beauvoir-Platz underwent intensive regreening. By 2023, Eva-Maria-Mazzucco-Platz in the Seeparkquartier was similarly transformed with additional greenery and cooling features. Under the slogan "Out of the Asphalt," one of Europe's largest and most innovative urban development projects took a significant step toward improving quality of life.
In 2023, over 1,100 square meters of asphalt were removed and greened. This effort included the creation of 12 new green beds planted with grasses, perennials, and shrubs. The design also introduced two square-like recreation areas with existing seating elements surrounded by green beds, providing shaded, pleasant spaces for relaxation.
The Eva-Maria-Mazzucco square was designed by a local NGO specializing in citizen engagement in urban development, while the project's overall initiation and implementation were led by the City of Vienna, the Donaustadt district, and Wien 3420 Aspern Development AG. This collaborative effort demonstrates how regreening initiatives can mitigate heat islands, foster urban biodiversity, and create more attractive, livable spaces. (Ref. 1-3)

The initiative involved the creation of three educational spaces in social service centers for children (Bucium, Ion Holban, Bogdanesti) in Iasi and its peri-urban area that included urban gardens, the development of green spaces, and facilities for sports activities. In the urban gardens, raised and arranged in a circular design, various orchards and food-producing plants were planted, along with bushes and perennial plants introduced in the new green spaces. Additionally, benches, workshop stations, a volleyball court, and a ping-pong table were constructed alongside the green areas.
The initiative was implemented by the NGO "Asociatia Outventure" and financed through the "In stare de Bine" program, funded by Kaufland Romania and managed by the Fundatia Pentru Dezvoltarea Societatii Civile (Foundation for the Development of Civil Society). The project also included training for permanent volunteers involved in the initiative and conducted 16 thematic workshops on healthy living and ecological behaviors.
The primary target group for the initiative was children and young people at risk of social exclusion, whose circumstances worsened after the COVID-19 pandemic. The objective was to provide them with "an alternative space to develop their personalities, as well as the necessary tools to adopt a healthy lifestyle in harmony with the surrounding environment." The project had a budget of 22,127 euros and was implemented over the span of six months. (1-5)

The Färjenäs Agroforestry Garden started in 2013 in the Färjenäs park in Hisingen, Gothenburg. A group of people interested in agroforestry started a study circle on the topic the year before and then formed an association to apply their knowledge in practice. The City of Gothenburg helped the project get started by providing some funding and finding a 2000 sqm spot for the garden on land owned by the city. The Färjenäs agroforestry garden association is run by volunteers, who have planted about 200 different species of trees, bushes and herbs that produce produce. The planting and management of the garden aims to promote soil health and biodiversity. The association received funding from the Swedish Environmental Protection Agency in 2020 and partnered with the Natural History Museum in Gothenburg to further promote biodiversity and wild pollinators, and has partnered with a local beekeeping association to establish a beehive in the garden. The garden is open to the public and invites the public to educational activities and working events such as planting. The association aims to be a meeting place for locals and visitors from all over the city, with different cultural backgrounds and generations. Several courses and educational programs within agroforestry, agriculture and gardening have been held at the garden. [Ref. 1-7]

In 2024, Ozanam (a housing private company) and the French Development Agency (AFD) formalized a partnership to modernize an ecological wastewater treatment plant in Saint-Joseph, a neighborhood in Fort de France. The project focuses on replacing an outdated 30-year-old installation that no longer meets current standards with a plant-based water filtration system based on the ‘Rhizosph’air’ patent. This innovative treatment process utilizes "filter gardens," which combine mechanical systems, a gravity network, and a phytoremediation approach. The system employs filters made of gravel and the roots of local plants, specifically Strelitzia reginae and Cyperus alternifolius, to naturally and effectively filter wastewater without odor (Refs 2, 3, 4).
The nature-based system purifies wastewater over an area of 2,000 square meters, with a capacity equivalent to serving 900 residents. This approach offers several advantages, including reduced maintenance costs due to its simplicity, decreased energy consumption compared to traditional treatment methods, and improved water quality released back into the environment (Ref 2). Beyond its technical efficiency, the filter gardens enhance biodiversity (Ref 2) by improving the quality of water discharged into the environment and providing habitats for various species. The solution also integrates seamlessly into the landscape, showcasing vibrant flowers native to the area (Ref 1).
Additionally, the project implementers plan to construct a walking path, provide recreational equipment, and install benches to encourage residents to utilize the area as a public green space (Refs 2, 5).

The city of Thessaloniki is tackling the energy crisis and climate change risks by prioritizing the installation of green roofs and green walls on school and municipal buildings as part of its resilience strategy, Thessaloniki 2030 (Ref 1, 2). One key project under this strategy has been implemented at EPAL Stavroupoli, one of the largest school complexes in the metropolitan area. The school, with a total built area of 11,918 sq.m and roof surfaces covering 6,042 sq.m, now includes a green roof covering 3,087 sq.m with 25,000 ground-cover plants, along with a vertical garden on three walls at the entrance, covering 100 sq.m and featuring 3,098 plants (ibid.).
The project is expected to yield multiple environmental benefits, such as reduced energy losses, improved thermal performance, enhanced sound insulation, better rainwater management, decreased runoff, and retention of harmful particles, all of which contribute to upgrading the area's green infrastructure (Ref 1). This initiative also strengthens the green fabric of western Thessaloniki and improves the local microclimate while addressing rainwater management issues (Ref 3, 4).

The project aims to protect seagrass meadows, which are vital habitats for the prey of resident dolphins and essential to the local fishing economy. The initiative involves local fisherwomen, called "Keepers of the Sea," in activities such as marine education, awareness campaigns, and monitoring the health of the seagrass meadows (Ref 1). Founded in 2015, Ocean Alive aligns with several UN Sustainable Development Goals, including ocean conservation, gender equality, quality education, and climate action (Ref 4). The project is supported by partnerships with UNESCO and other organizations, and it extends its efforts to Portuguese-speaking African countries. Ocean Alive’s activities also include advocacy for blue carbon ecosystems and programs that involve community engagement and social innovation (Ref 2, Ref 5).
One of several implementation projects targeted safeguarding the young seagrass meadow at Cambalhão Bay, at the entrance of the Sado estuary, as an Ocean Alive’s initiative in partnership with SeaTrees by Sustainable Surf (Ref. 2). The Cambalhão meadow is made up of 202 patches of seagrass. Unregulated shipping is one of the factors in the degradation of the prairie, and to protect it, Ocean Alive is running a campaign to raise awareness about recreational boating (Ref. 6).

The Helmut Zilk Park, named after the late Mayor of Vienna, is located in the heart of the city, near the central train station. Surrounded by newly constructed residential and office buildings, the park serves as a vital green space, offering a variety of amenities. From playgrounds and sports fields to a community garden and cafés, it provides a space for social interaction and recreation. The park is characterized by large open meadows, which function as rainwater seepage areas, and features over 500 trees along its pathways., as well as community gardens. Flower groves enhance the park’s visual appeal while also providing habitats for local wildlife. The natural edges of the park create a diverse urban biotope that supports various plant and animal species. Grass and meadow communities have been carefully planned to enhance biodiversity and provide wet, humid habitats that help infiltrate rainwater from the surrounding paved areas. Already in its first year, the park has become home to insects, small animals, and even larger species like rabbits and snakes, contributing to its rich ecosystem.
The park was developed by the local municipality of Vienna on a site that was once part of the city's railway track system. It is the largest park the city has created in the past 40 years, designed to serve as a recreational area for both local residents and travelers using the nearby train station.
This project is part of a broader urban development initiative around the former Southern Railway station, led by Austria’s Federal Railways Company (ÖBB) and the City of Vienna. The plans included residential housing, office spaces, social infrastructure, and the creation of the Helmut Zilk Park.
Spanning approximately 70,000 square meters, the park stands as the largest public green space created in Vienna in four decades. The central area of the park features a large lawn, perfect for picnics, ball games, and recreational activities. (Ref. 1, 2, 3, 8)

Minimizing heat stress is a critical priority for Phoenix, the hottest major city in the U.S., where heat-related deaths reached at least 359 across Maricopa County last year. The city's expansive urban layout and infrastructure exacerbate the urban heat island effect, making an already scorching climate even more hazardous. In addition, heat impacts communities unequally, with some neighborhoods up to 10 degrees hotter than others. Lower-income and predominantly Hispanic neighborhoods often have less canopy cover and fewer resources to combat rising temperatures, making them more vulnerable to extreme heat.
To address this, the City of Phoenix launched the Cool Corridors Program in 2020, a key initiative in its broader climate resilience strategy. This program, a partnership with American Forests and the Phoenix Street Transportation Department, aims to establish a network of shaded pathways that connect communities across the city. These corridors enable residents to travel safely to schools, public transit, and other city hubs, promoting environmental sustainability and public health.
The program prioritizes investment in low-income, heat-sensitive neighborhoods to improve tree equity and create green spaces where they’re most needed. The first Cool Corridor was developed in 2022 at Cesar Chavez Park, where over 250 trees were planted with the support of more than 100 volunteers, setting a strong example for future initiatives. By 2030, Phoenix plans to complete 100 Cool Corridors citywide, building a more resilient and livable urban environment for all residents. (1-5, 7-8, 10)

The Museum of Art, Architecture and Technology (MAAT) features a 2,920-square-meter green roof (Ref 8). Located on the riverfront of the historic Belém area in Lisbon, MAAT, inaugurated in 2017, comprises the repurposing of a thermoelectric power station built in 1908 (MAAT Central), a contemporary museum building (MAAT Gallery), connected by a garden that stretches along the Tagus River (MAAT Garden) (Ref. 3).
Blending structure into landscape, MAAT was designed to allow visitors to walk over and under its building, in which "the roof becomes an outdoor room, a physical and conceptual reconnection of the river to the city’s heart – where visitors can turn away from the river and enjoy the vista of the cityscape, and at night, watch a film with Lisbon as a backdrop sitting on the bank of steps" (Ref. 1). This roof, part of AL_A’s (design company) architectural vision, offers panoramic views of Lisbon and the Tagus River (Ref 1), and complementing the green roof is a 225-meter-long garden designed by Vladimir Djurovic, which connects MAAT to the Central Tejo power station. This garden features diverse vegetation (Ref 2, Ref 3, Ref 4).

Välen is a natural area 8 km south of central Gothenburg, established as a protected nature reserve in 2013. Prior to the establishment of the nature reserve, Välen was an agricultural area that experienced environmental degradation due to pollution from a nearby sewage treatment plant. Västra Frölunda Nature Conservation Association leased the land in 1985 in order to allow cattle to graze through the overgrown meadows as a form of landscaping approach [Ref. 5].
The City of Gothenburg took the initiative to protect and manage the area as a protected reserve [Ref. 1, 2]. It is formed of wet meadows and deciduous forests and has a total area of about 68 hectares, of which 52 ha are land and 16 ha are water. Välen is situated by the sea and the mouth of a small river, and protects some of the coastal waters. Residential areas surround the nature reserve and are a popular destination for recreation [Ref. 1-3]. In creating the nature reserve, efforts were made to make the area more accessible to visit and to provide learning opportunities. New paths, entrances and signs were established [Ref. 3-4]. The nature reserve is described as contributing to several national environmental goals, particularly goals related to biodiversity [Ref. 2].