Developing nature-based therapy for health and well-being Nature affects human health in different ways. In particular, urban environments can have a negative impact on physical and mental health. This is due to urban stressors such as increased noise levels, higher crime rates and higher levels of pollution. The total global burden of disease attributable to mental illness has recently been estimated to be as high as 32% of total years lived with disability and 13% of disability-adjusted life-years, on par with cardiovascular and circulatory diseases. It is important, therefore, to determine the degree to which nature experience might lessen and address this burden. Even more so in view of the fact that the opportunities and time spent in nature are decreasing. However, despite many putative positive correlations identified between nature and health and well-being, the causal understanding of relationships between health and nature exposure are not well understood. The long-term effects are also less well studied and recognised in policies. Social, economic and cultural factors strongly mediate the strength and direction of linkages between health and nature. Age, gender and especially socio-economic status may modify the association between greenness and health behaviours and outcomes and need to be better understood to create more effective nature therapy. Additionally, mental health benefits may vary with the type of interaction with nature and the form of sensory input. Furthermore, the health and well-being benefits of exposure to nature are affected by cultural perspectives and experiences relating to social interaction and contact with the natural environment. A successful proposal should:Develop a common framework to increasingly recognise and promote contact with nature, including protected areas and other green and blue spaces, as a cost-effective response for the prevention and treatment of human health and well-being;Propose an interdisciplinary and cross-sectoral approach, including the involvement of the health care sector, land owners, as well as green space management and nature protection sectors;Improve schemes monitoring nature-health linkages to enhance the evidence base and tools for the health care sector, green space management, nature protection, urban planning and landscape architecture;Develop longitudinal prospective methods, (quasi-) experiments or well-controlled interventions, to provide more evidence of the causal relationships between nature and health and well-being: Understanding of when people explicitly choose to go to an urban green space and what experiences they have there (e.g. active versus passive activities). Determining the type of interactions and dose of interactions necessary for long-term health and well-being benefits. Understanding the mediators of the health-nature relationship, such as age, gender, socio-economic status or culture. Considering the difference between greenness quantity and quality and determining which aspects of natural features are relevant to mental health. Understanding how different geographical locations and factors such as population density affect the health-nature relationships; Test nature therapy sessions, identify best-practices and develop the necessary tools and guidelines for integration of nature-based care in the public health sector;Identify legal and administrative arrangements, partnerships, and financial mechanisms for implementation of nature therapy sessions. The proposals should address all of the above points. Proposals should bring together from the start multiple types of scientific expertise in both health and natural sciences, as well as social sciences and humanities, together with a variety of community and health sector representatives, businesses, civil society organisations and citizens.Proposals should ensure that all evidence, information and project outputs will be accessible through the Oppla portal (the EU repository for nature-based solutions)[[https://oppla.eu/.]].Applicants should create synergies with projects under the same topic and other relevant ongoing or up-coming projects, notably the Horizon 2020 NBS project portfolio and its task forces; HORIZON-CL6-2021-BIODIV-01-05: The economics of nature-based solutions: cost-benefit analysis, market development and funding; HORIZON-CL6-2022-BIODIV-01-03: Network for nature: multi-stakeholder dialogue platform to promote nature-based solutions; HORIZON-CL6-2022-COMMUNITIES-01-05: Assessing the socio-politics of nature-based solutions for more inclusive and resilient communities; HORIZON-CL6-2021-COMMUNITIES-01-06: Inside and outside: educational innovation with nature-based solutions. To this end, proposals should include dedicated tasks and appropriate resources for coordination measures, foresee joint activities and joint deliverables.Social innovation is recommended when the solution is at the socio-technical interface and requires social change, new social practices, social ownership or market uptake.In order to achieve the expected outcomes, international cooperation is strongly encouraged, in particular with the USA, Japan and the LAC region.This topic should involve the effective contribution of SSH disciplines.