This thesis aims at the landscape architecture of the enclosed garden as an expression of the genius loci: definition, analysis, typology and transformation. The process of metropolisation tends to eliminate, or at least hide, the underlying landscape. The research addresses the question of how the genius loci can be made accessible in the metropolitan landscape, focusing on the concept of place. Can place be designed? The metropolitan landscape is understood here as the spatial expression of the profound mix of city and landscape, nature and culture, production and consumption, the far-reaching influence of urbanity. This global phenomenon leads to a diffused and fragmented landscape with many different spatial conditions, existing next to and on top of each other, in a constant process of formation. If a garden - the classical means of expressing the landscape - is also capable of expressing metropolitan conditions, then we may call it a metropolitan garden. These conditions could be the generic, metropolitan condition that has led to its existence - such as the landscape of infrastructure or the skyscraper landscape - or they could have emerged as the garden developed and matured. The metropolitan garden, as a defined space in the continuous metropolitan field, as well as an anchor point to the landscape topography, provides an alternative way to access the landscape horizon, the reference to nature, and the connection to the underlying landscape. In the landscape architecture of the metropolitan garden, artificial and natural can no longer be viewed as complementary notions. The garden as an abstraction of nature is thus an experimental playground of the metropolitan landscape. This form of abstraction can be called ‘super-nature’: sensory nature, brought close to man, part of daily life, and part of the metropolis. It is as artificial as it is natural, bringing together the architectural and the ecological view of the 20th century. The processes of time, growth and decay, whimsicality, abundance, rough materials, and tactility, play a large part in the contemporary metropolitan garden. The processes of nature, growth and decay, whimsicality, abundance, rough materials, and tactility, play a large part in the contemporary metropolitan garden. The notion of place is elaborated upon as the inherent characteristics of a geographical location, which are perceivable as a coherent ensemble, different from its surroundings. Yet it is also the surroundings which determine at least part of these characteristics. In order to be defined as ‘place’ three components are at play. Firstly, it is meaningful: there is an affective bond between people and place (sense of place). Secondly it is determined by its landscape characteristics (‘personality’ of the location). Both are united in a definite space, on the scale of the human being, small in relation to the scale of landscape (third component: definition of form). Since it is already determined by its landscape characteristics, place cannot be designed, but it can be made accessible by design: through form place becomes perceptible. The garden asserts the hidden qualities of the location and denotes the location as a place. The opportunity interstitial gardens offer for the metropolitan landscape, is that they can function as places outside, juxtaposing their metropolitan context by emphasising specific locations, and reflecting the landscape from the margins of the metropolitan tissue. These marginal spaces could be developed into an interstitial strategy of metropolitan gardens: a new layer of precise anchor points to the genius loci.