Poor urban planning in the past caused, that this part of Prague lacks public infrastructure, including kindergartens. One of the few possible building sites happened to be a grassy area in between older apartment buildings. The demand is high and up to 230 kids have to be placed there. We knew the background conditions were not ideal, therefore we wanted to make the building invisible. Hide it from the neighbors, but keep the grassy space as much as possible at the same time. This led us to the idea to bury the kindergarten and use its roof for a public park. This solution also means the future building will have a passive energy standard. Deep underground heat pumps will be connected to floor heating. The roof overlap provides shading and prevents from overheating. In order to let the light in, the inner courtyard had to be designed in an appropriate scale. This allows even the lower playrooms to have good lighting conditions. These rooms are divided into two parts. The one closer to the openings is the play area, the other one further away from the openings is for sleeping only. The entire structure will be made of reinforced concrete with visible wooden board pattern. The inner courtyard will be paved with soft playground surface. Other, more natural playground will be further away and will feature a hill made of excavated earth from the site.