A tower-like vertical axis wind turbine, comprising a cradle-like supporting structure including and supporting a rotor with vertical axis, coaxial thereto, with a central shaft connected to an electric generator, wherein: • the rotor extends between two horizontal bases (8,13) formed like a disk, welded to the central shaft supported by said supporting structure by means of bearings at respective basements (9,15) of the latter, the periphery thereof of said rotor is connected by means of a crown of vertical blade axes parallel to the central shaft, on each one is engaged a vertical blade which has a horizontal section of concave-convex type (11,12), the blade being apt to be rotated by 90° around its own axis; • each blade is hung to an upper small disk placed below the upper base of the rotor, the upper small disk being driven to rotate said blade therewith; • the blade engages on the lower side to a respective lower small disk, arranged above the lower base of the rotor, in a pair of cross-like grooves in said lower small disk: a first groove arranged tangentially and a second one arranged radially, both ones formed on the upper surface of the lower small disk, the lower small disk being housed in a cavity of the lower base, provided with vertical grooves wherein respective spines of the lower small disk are inserted, allowing the translation thereof according to a vertical axis but which prevents the rotation thereof so as to constrain the blade when it is engaged in said cross-like grooves; • the cradle-like supporting structure is swivelling so as to have the same up-wind and down-wind side, the cradle-like supporting structure comprising: a first device of rotation of the blades arranged up-wind, to rotate by 90° the respective blades by changing the orientation thereof from tangential to radial; and a second device of rotation of the blades arranged down-wind, to rotate by 90° the respective blades by changing the orientation thereof from radial to tangential, both rotation devices acting so as to disengage or engage in the respective lower small disks the lower ends of the blades in said grooves, by making said lower small disks to go up and down, the blade remaining hung to the upper small disk, said blade and the respective lower small disk being kept in axis by said vertical blade axis; so that the blades at the second device arrange tangentially with the respective concave side directed towards the inside by lining up to a half-cylindrical group of concatenated blades lying on the side of the rotor against the wind, whereas the blades at the first device, by detaching from said half-cylinder, arrange radially, so that the blades lying on the side in favour of the wind show the concave side thereof to the wind direction; and so that, by activating the second rotation device only it is possible to arrange all blades tangentially to form a complete peripheral cylinder so as to close to the wind said wind turbine. • the rotor extends between two horizontal bases (8,13) formed like a disk, welded to the central shaft supported by said supporting structure by means of bearings at respective basements (9,15) of the latter, the periphery thereof of said rotor is connected by means of a crown of vertical blade axes parallel to the central shaft, on each one is engaged a vertical blade which has a horizontal section of concave-convex type (11,12), the blade being apt to be rotated by 90° around its own axis; • each blade is hung to an upper small disk placed below the upper base of the rotor, the upper small disk being driven to rotate said blade therewith; • the blade engages on the lower side to a respective lower small disk, arranged above the lower base of the rotor, in a pair of cross-like grooves in said lower small disk: a first groove arranged tangentially and a second one arranged radially, both ones formed on the upper surface of the lower small disk, the lower small disk being housed in a cavity of the lower base, provided with vertical grooves wherein respective spines of the lower small disk are inserted, allowing the translation thereof according to a vertical axis but which prevents the rotation thereof so as to constrain the blade when it is engaged in said cross-like grooves; • the cradle-like supporting structure is swivelling so as to have the same up-wind and down-wind side, the cradle-like supporting structure comprising: a first device of rotation of the blades arranged up-wind, to rotate by 90° the respective blades by changing the orientation thereof from tangential to radial; and a second device of rotation of the blades arranged down-wind, to rotate by 90° the respective blades by changing the orientation thereof from radial to tangential, both rotation devices acting so as to disengage or engage in the respective lower small disks the lower ends of the blades in said grooves, by making said lower small disks to go up and down, the blade remaining hung to the upper small disk, said blade and the respective lower small disk being kept in axis by said vertical blade axis;