The urban microclimatic conditions in the Mediterranean can become very harsh during the summer because of the intense solar radiation and the elevated air temperatures. Athens, Greece is characterised by very hot days, with temperatures, which may reach up to 38 degrees Celsius, while its urban squares are generally deprived of vegetation and water elements. This paper attempts to give an answer to these problems by proposing a multi-functional bioclimatic structure for the open spaces of Athens. It is a structure, which provides shading, cooling, and has the ability to move its parts. Shadum Evaporatis is an autonomous, eco-friendly tree, whose ambition is not to substitute real trees, but to provide, in cases where planting trees is not possible, shading and evaporation. It can also be seen as a city landmark, a path-finding element, and an object, which changes during the day and throughout the year. It is a design object for urban open spaces, which can be natural and low-tech, or sophisticated and high-tech object, depending on variations of its design.