“Marina One”, a high-density, mixed-use building complex in the heart of Singapore’s new Marina Bay financial district, complements the Urban Redevelopment Authority’s (URA) vision of making Singapore a “City in a Garden”. Marina One is green in both a literal and performative sense. Flanked by two large urban parks, it comprises two office towers, two residential towers and a retail podium set around lush greenery. While the outer face of the four towers strictly follows the city grid, the maximised inner space is a free-formed three- dimensional biodiversity garden. Openings between the high-rises, sky gardens in- between the podium, the elevated towers, as well as the shape itself, improve the air flow and create a comfortable microclimate within the multiple levels of the central garden that covers up to 125% of the site area. In addition to a compact and efficient building layout, the environmentally-smart design also features energy-saving ventilation systems, a highly effective external sun-shading system and high performance glazing to reduce direct solar radiation into the building. NEWater (centrally provided recycled water) for toilet flushing and a rainwater harvesting system reduce water consumption. PV cells make use of the sun’s energy. Furthermore, the direct connection to four out of the six Singaporean MRT lines and bus stations as well as the provision of bicycle parking spaces and e-car loading lots significantly reduce emissions caused by individual traffic.