There is provided a solar still apparatus for converting contaminated water contained in a contaminated water body into distillate water, the contaminated water body having a water surface, the solar still apparatus comprising a cover in the form of a geometrical projection comprising a wall, an opening and a chamber, wherein the wall is adapted to be in thermal communication with the external environment for capturing solar heat and in optical communication with the opening for allowing passage of solar rays from the external environment to the opening; the opening is adapted to be in optical communication with the wall and the surface of the contaminated water body for allowing passage of the solar rays from the wall to the surface of the contaminated water body for heating the contaminated water to form a vapor, and adapted to be in fluid communication with the surface of the contaminated water body and the chamber for allowing passage of the vapor from the surface of the contaminated water body inside the chamber; and the chamber is defined by the wall, the chamber being adapted to be in fluid communication with the opening for receiving the vapor formed and condensing the vapor for forming condensed distillate water therefrom.