A wall-drawing hovering device (WDHD) is provided. The WDHD comprises an unmanned helicopter configured and operable for flying and hovering while being disconnected from ground. The WDHD further comprises a mobilizing system comprising at least one motorized wheel. The mobilizing system is physically associated and carried with the unmanned helicopter and configured to drive the WDHD along a vertical surface when the WDHD hovers above ground. The WDHD further comprises a drawing system comprising a paint releasing member connected with a paint reservoir. The drawing system is carried with the unmanned helicopter and configured to controllably release paint from the paint reservoir through the paint releasing member. The WDHD is thereby configured to hover above ground next to a vertical surface such as a wall, so that the mobilizing system frictionally attaches to the vertical surface thereby enabling driving the WDHD along the vertical surface. The WDHD is further configured to draw on the vertical surface by controllably releasing paint from the paint releasing member.