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The Mediterranean climate in Lisbon, already characterised by low precipitation, has been further exacerbated by climate change. The city faces challenges related to biodiversity loss, urban loneliness, and climate anxiety (1). To address these issues, Lisbon's urban development plans have prioritised the re-naturalisation of urban spaces and the integration of ecological networks. Urban nature is now a central component of the city's Master Plan (2012) and other strategic agendas (1).
It is being developed by the LISGREEN project, which aims to enhance ecological connectivity and mitigate the effects of urban heat islands in Lisbon. By establishing nature-based solutions, it aims to restore forests within the city (1, 2, 3). This project encompasses different strategies, such as the RENATURA pilot project. It is a collaboration with the NGO URBEM and involves active public participation in tree planting and forest maintenance. This initiative aims to educate the community about nature, promote well-being, and mitigate extreme climate events (1), through the creation of urban forests.
The main strategy is to create fast forests using the Miyawaki method, which involves dense planting of native trees, removal of invasive plants, and intensive initial care. This approach accelerates the growth of natural forests within a short period, using native species and reducing the need for watering (1)
The first fast forest was developed in Parque Casal Vistoso within Bela Vista Park, within the Eastern Green Corridor of Lisbon. The park is being underutilised because of the lack of shade (1). Thus, this initiative encouraged volunteers to participate in tree planting and forest maintenance activities (3). The NbS intervention began with a 300m² experimental plot near the Vale da Montanha pedestrian bridge and has since expanded to a new 1,500m² plot on the opposite side of the bridge (2). Over 500 volunteers joined the effort, planting more than 3,800 trees (1)

Public spaces in Colombo are disappearing due to rising land prices, causing infrastructure issues that harm citizens' health, especially in low-income areas (3). One proposed solution to address the problems caused by rapid urbanization is the creation of community gardens, which can at least improve low-income residents' diets and immune systems and address malnutrition (3).
Considering the limited urban space for both citizens and other living beings, the organization Eco-friendly Volunteers decided to create a community garden. The Metta Garden in Colombo (1, 2) aims to bring back urban biodiversity through organic home gardening, generating healthy food for people and creating living space for many other animals and plants (2). Following the Buddhist concept of Metta (loving-kindness to all beings), it promotes walking meditation paths and facilities to experience nature using all five sensory organs (1), in addition to being a place for experiencing loving-kindness for both human and non-human living beings, seen and unseen (4, 5).
It has become a training institute for many stakeholders seeking to grow organic food and earn a better income through the high demand for organic products (2). At the same time, it serves as a biodiversity spot, attracting butterflies, bees, and other forms of wildlife to an urban environment (2).
The area is located in the middle of a semi-urbanized area, on the outskirts of Boralesgamuwa (2, 3). Maintained by a group of volunteers, it features a greenhouse and a plot of land of around 5,000 sq feet, populated with vegetable patches, a butterfly garden, flowers and rare medicinal plants (3, 4). The garden was divided into four sections representing the Buddhist elements: water, heat, air, and solid. Each section features specific plants and designs, like a pond for water, a compost pit for heat, tall plants for air, and a rock garden for solid. The layout follows a mandala design based on permaculture principles (4).

Located in the municipality of Morne Rouge, the Domaine d’Émeraude was once an agricultural site but was transferred to the Martinique Regional Natural Park (PNRM) in the early 2000s. It underwent significant renovations in 2005 to transform it into a sanctuary for Martinican biodiversity, reflecting the need to protect and conserve the island's unique ecosystems. In 2011, it opened its doors to the public, serving as an important educational resource that raises awareness about the island's historical, natural, and cultural heritage (Refs 4, 7, 8).
Today, the site encompasses 25 hectares protected from anthropogenic pressures and is primarily characterized by a humid tropical forest environment, which makes up 80% of the area (Ref 7). It is home to over a hundred native species (Ref 4) and offers nearly 4 kilometers of walking trails accessible to both adults and children, complete with recreational stops and educational amenities.
The Domaine d’Émeraude was designed to enhance the conservation of native species while developing sustainable economic activities that benefit the local community. Moreover, the site emphasizes the well-being that forested areas provide to visitors, highlighting that "the air can be heard, the smells can be savored, and the sounds can be experienced. The freshness of the place is a source of change and relaxation..." (Ref 4).

In Berlin, at the palace park and garden Charlottenburg, approx. 40 to 70 horned Gotland sheep are used to maintain the grass fields and meadows. The project is part of a garden and landscape conservation programme that is to be seen as a contribution to practical nature conservation by the Prussian Palaces and Gardens Foundation Berlin-Brandenburg, which manages the park. From May to November, the sheep are grazing on the palace property, whereby the exact length of time the sheep are kept and the duration of the project depend largely on the developing weather conditions. This is because prolonged drought significantly reduces the growth of the grasses. (Ref. 1)
The garden had already been grazed earlier in its history, but no longer in the post-war period. The garden was created by Electress Sophie Charlotte in 1695. (Ref. 3) Since 2018, sheep can be found again in the park space where they graze on extensive meadows with groups of chestnut, lime, maple, oak, beech and solitary trees. At the beginning of May, they move into their first station there, usually the meadow in front of the late baroque-classical Belvedere tea house. Once this has been grazed, they move on to the next meadow; with an area of 55 hectares, there is plenty of pasture. (Ref. 4)
Sheep from his flock also graze on the green flat roof of the Max-Schmeling-Halle in Pankow, the palace garden of Sanssouci and other public and private patches of land around Berlin. Reasons to use sheep over machinery for the maintenance of the park space are monetary and a reduce loss of biodiversity. Sheep are cheaper compared to machinery, the needed labour and wear, and also don't kill insects living in the fields as machinery does. Furthermore, the sheep dung fertilises the grass area, sheep limit the spread of invasive plants and are more gentle to the soil. At the same time, palace visitors enjoy observing the sheep and can learn about them in guided tours. (Ref. 4; Ref. 6)

The schoolyard at Reginhard Primary School in Reinickendorf faced persistent challenges, often becoming unusable due to poor drainage. After rainfall, water would pool, leaving the yard submerged and inaccessible to the 400 primary school pupils. Even in dry weather, the schoolyard was far from ideal: a lack of play equipment made it uninviting, and in summer, the area became excessively hot, offering little comfort or shade. Both children and the school community, including teaching staff and parents, voiced a strong desire for improvement.
Adding to the urgency for redesign, Berliner Wasserbetriebe imposed a discharge restriction, requiring rainwater to be managed on-site. This led to a comprehensive transformation of the school grounds. Large areas were unsealed, allowing water to seep naturally into the ground. Underground seepage systems were installed to enhance drainage, and the redesign introduced green spaces, a school garden, and near-natural play and exercise areas. These changes not only resolved the flooding issue but also created a more inviting and sustainable environment for students.
The focus on ecological and sustainable design improved the microclimate, providing cooler surroundings and enabling outdoor breaks filled with activity and fresh air. The redesign transformed the schoolyard into a vibrant space that meets the needs of both children and the environment.
This project was funded by the Berlin Programme for Sustainable Development (BENE Umwelt) and financed by the European Regional Development Fund (ERDF). (Ref. 3; Ref. 4)

Established in 1996, the United Nations Office at Nairobi (UNON) is the UN's official headquarters in Africa, located just 9.7 km from the heart of Nairobi. In line with the UN's global sustainability goals, the office took significant steps to reduce its environmental footprint as it expanded. According to the United Nations Environment Programme (UNEP), buildings contribute to a third of global energy use and are major sources of greenhouse gas emissions. To address these issues, new buildings were designed to prioritize energy and water efficiency, with a focus on sustainability.
Completed in 2011, the new headquarters reflect the UN's broader commitment to reducing greenhouse gas emissions. The design includes 6,000 m² of solar panels, rainwater harvesting systems, energy-efficient lighting, and natural ventilation, making the complex energy-neutral and water-efficient. It generates as much solar energy as it consumes, supporting over 1,200 staff members. Additionally, the project carefully preserved indigenous trees and created micro-ecosystems within the interior gardens, further aligning with the UN’s environmental mission.
By embedding these green features, the UNON complex serves as a model for sustainable development in urban settings, echoing the UN’s efforts to combat climate change and promote ecological resilience globally. (Ref. 1, 2, 3, 4)

The John Michuki Memorial Park was transformed from a vast dumpsite in 2008 and established in honor of John Michuki, the Environment Minister during the Kibaki administration, in 2012. Michuki garnered admiration and accolades for his enthusiasm and determination to clean and preserve the environment (Ref 1, 2). Situated along the Nairobi River, the park serves as a historically rich recreational facility (Ref 3).
However, several issues arose after the park was transferred to the county administration in 2013 (Ref 2). A section of the Nairobi River flowing through the park experienced severe environmental degradation due to illegal discharges and poor waste management, negatively impacting the riparian ecosystem and biodiversity (Ref 4). Additionally, the park became a refuge for drug users, street children, and thieves, with stray dogs posing safety threats in the area (Ref 1, 2).
As the first project within the Cleaning Up Kenya Campaign, the restoration of Michuki Memorial Park was launched in 2020 by the government (Ref 5). The park is now managed by the Kenya Forest Service (KFS) following a directive from the national government (ibid.). With funds from the treasury, a perimeter fence was erected, a 2.4 km walkway was constructed, and 4,200 seedlings and 6,357 indigenous trees were planted, along with the establishment of a nursery (Ref 1, 6). A total of 20,000 tons of solid waste were removed (Ref 6). Additionally, a community forest association was formed to ensure community engagement (Ref 2).

Located in the Lima district of San Isidro - the heart of commercial activity in Peru - the Real Dos Tower is a prime office building in the Centro Empresarial Real de San Isidro. It was inaugurated in 2018, and it is distributed over 23 levels (14 floors and 9 basements) and enjoys a landscaped green roof (1162 m2) at the crown of the building and numerous outdoor vertical gardens at full height (2365 m2) on the three main fronts (1, 4). This project was a finalist in the 2018 Mipim Awards, considered the ‘Oscars’ of world architecture, and stood out for its architecture and design, due to its attributes of innovation and sustainability (2).
This building has managed to create harmony between design and efficient use of resources. It is characterised by a glass façade with colourful movable shutters and symbolic Peruvian designs (2, 3, 6). It has green walls on the three main fronts, four daylight fronts and a roof garden (2). The architect, Jean Nouvel, worked together with ARVE Peru on the overall landscape plans for the Real Dos tower (1, 3).
This is part of the façade remodelling project of the Camino Real Towers in the Real Business Centre, led by the real estate company Grupo Centenario (1, 2, 3, 4, 5, 6). This overarching Project has sought to develop 4,475 m2 of vertical gardens and roof gardens, which have a technified irrigation system to generate efficiencies in water use, meeting the plants' water requirements in the different seasons of the year. Their implementation helps to filter CO2 and renew the O2 in the office complex.
The ARVE group describes these actions as conducive to creating thermal barriers and sound insulation, a better environment for rest, work and entertainment and increasing property value (7)

The urban farm of Lak'a Uta is an initiative launched by the NGO Fundación Alternativas, which established the first community garden in Bolivia, located in the city of La Paz at an altitude of 3,600 meters above sea level (1-3). The initial plan was to develop the garden on private land, but since the goal was to create an open space accessible to all citizens, the project eventually sought a public location (3). The subdistrict of Cotahuma granted them permission to use the Lak'a Uta park, an abandoned area rendered unusable by two landslides in the previous year (3). Through voluntary efforts and an investment of 2,800 euros, the land was transformed over three years to accommodate 40 plots of 16m² each, with individual families cultivating a variety of vegetables (3).
Now celebrating its 10-year anniversary, the project adheres to many principles of organic agriculture in an urban setting (5). The area has become a biodiversity hotspot, featuring an artificial pond, 16 wild plant species, and 39 fauna species, including 34 bird species, two types of frogs that provide natural pest control, and three bee species (3-5). Compost is produced naturally using waste management practices and worms (4-5). In addition to edible vegetables, the garden produces medicinal plants, some of which help stabilize the soil and prevent further landslides (3-4). The infrastructure also includes a rainwater collection system (3-5).
Originally, the project aimed to improve access to food, particularly in response to the growing urban population (1-3). Over time, it has also fostered a strong sense of community, while promoting urban gardening through educational workshops and disseminating information nationwide (1-5). It is estimated that 20,000 people have been educated on urban agriculture, healthy eating, and reconnecting with nature (5). The project has also contributed to shaping a local government law supporting urban gardening within the municipality (3).

Thessaloniki, Greece's second-largest urban center, is a key hub for economic growth and outward trade in the Balkans. The city hosts the country’s second-largest export port, which plays a crucial role in connecting European trade routes with Asia and China. However, until 2014, Thessaloniki's waterfront was poorly maintained, largely inaccessible, and unattractive. Moreover, major flooding events, connected to extreme weather events, exposed significant deficiencies in the city's flood mitigation infrastructure, leading to damage to housing and critical services. (5, 10, 11)
To address these issues, the Municipality of Thessaloniki launched an International Architectural Competition for the redevelopment of the New Waterfront. From 2006 to 2014, Thessaloniki's waterfront underwent a significant regeneration aimed at benefiting the city's population of 1.1 million and stimulating the local economy. The revitalized waterfront now stretches 3 kilometers between land and sea, featuring 58,000 acres of green space an playgrounds.. In total, 2,353 new trees and 118,432 plants were added across an area of 238,800 m² (Refs 1, 3, 4).
The project also introduced walking routes, sports and recreational facilities, seating areas, and scenic viewing points. The waterfront now has a bicycle path along the entire walkway, and an arbour of 660 umbrella pine trees, serving as shade from the midday sun. Completed in 2014, the New Waterfront has already become a vibrant urban green space, enjoyed by both Thessaloniki's citizens and visitors alike (Ref 4).