Increasing demands for the restoration of nature in cities have led planners to seek an effective form, configuration and maintenance scheme for parks and open spaces in urban areas. This paper aims to introduce two contrasting examples of ways that planners have met the challenge of restoring nature in the city. It takes Tokyo Bay Bird Sanctuary Park (TBBSP), Tokyo, Japan, and Tommy Thompson Park (TTP), Toronto, Canada, as case studies. TBBSP is located on reclaimed land facing Tokyo Bay, and is surrounded by heavily industrialized areas. The absence of green corridors which connect TBBSP to surrounding green patches have turned TBBSP into an isolated oasis for migrating birds. TTP in Toronto is also located on reclaimed land facing Lake Ontario. However, TTP has become to be an indispensable green patch of the open space network of Toronto because it is located at the node of green corridors. The principles of landscape ecology may dictate that TTP, integrated in the green network of the area, is in far better condition than isolated TBBSP. However both case studies are based on the same early post-war parks and open space planning concept, which aimed to clearly separate urban greens from surrounding urban fabrics. To restore nature in cities it is important to understand that alternative models of parks and open space planning can exist. We therefore refer to the authentic urban pattern found in Japanese cities, which historically have not intended to clearly separate each land use types but have sustained a mix of open spaces and urban fabrics. In the context of the global concern to realize ecological cities, restoring a city by integrating greens in the urban fabric should be understood as a way of achieving a “city in nature”.