The increased number of people living in urban areas requires rethinking what liveable citiesLiveable cities are about. Within the next decade both climate change and the shortage of resources on water, energy and nutrients will have strong impacts on the urban environment. The big challenge is to create ‘healthy citiesHealthy cities’. Bringing landscapeLandscapes to the citiesCities can strongly contribute to making citiesCities healthier, more resilientResilient, and more vibrant to accommodate all their citizens. The key to this new perspective is how to create healthy citiesHealthy cities in densely built areas and strengthen the urban metabolismUrban metabolism, while also addressing externalities, such as the urban heat island effect, increased storm events and sea-level rise. The objective of this chapter is to gain insight in the new complexity that arises from the increasing relevance of landscapeLandscapes and planting in dense urban environments in order to set a contemporary agenda for urban green spaceUrban green spaces designDesigns. The increasing need to develop healthy, circular and climate adaptiveClimate adaptivecitiesCities leads to new demands on urban green spacesUrban green spaces. By rebalancing traffic in citiesCities, a vibrant and green public realm can be realised. Rebalancing transportation and shifting to multimodal mobility has a large impact on the spatial qualitySpatial quality of citiesCities and provides access to all. The public realm can be transformed into a green and blue network and set the scene for vibrant cityCities centres. The complexity that arises from the new demands on green space in dense urban environments is explained through the analyses of four case studies in Rotterdam, Athens, London and Utrecht, combined with literature reviews. These four ‘research by designDesigns’ projectsProjects are discussed and evaluated to reveal the increasing (societal) relevance of urban green spaceUrban green spaces. These projectsProjects offer new perspectives on the integration of climate adaptiveClimate adaptive designDesigns and circularity. Toolboxes for heat mitigationHeat mitigation and water-sensitive designDesigns are developed and applied in these designsDesigns. Today’s imminent need to increase the degree of self-sufficiency within cityCities limits and regions, as well as climate adaptationClimate adaptation, requires continuous monitoring of the level of incorporation of the different aspects of ‘healthy living’ into the realized development and assessment of the standards each year. Adding today’s aspirations for including biodiversityBiodiversity, calls for the idea of ‘urban biotopesUrban biotopes’, turning the green into an urban ecosystem that can evolve over time. It requires careful considerations about how to balance energy generation and green, and how to integrate underground infrastructure, to make sure that proper conditions for urban green are set.