A metal structure, comprising: a plurality of hollow structural members (2a, 2b, 2c), each structural member having two inner planes (2b 1, 2b 2) each with two non-threaded holes (5a, 5b, 5c, 5d) at both ends and a plurality of threaded holes arranged in between said non-threaded holes (5a, 5b, 5c, 5d), said holes positioned at a distance "Y"; a plurality of die-cast heavy duty corner modules, each corner module comprising a base cube, the base cube having an "M" threaded hole (A 3) and three rectangular block shaped protrusions (1 b, 1 c, 1 d) extending outwardly from three adjoining faces of the base cube, each rectangular block-shaped protrusion (1 b, 1 c, 1 d) having two threaded holes in each inner wall of the protrusion, wherein said holes are positioned at a distance "Y", wherein said protrusions are configured to receive the end portion of the structural members (2a, 2b, 2c), such that the structural member (2a, 2b, 2c) is slidably insertable to the protrusion and fixable together with the use of screws (3a-3f), that pass through the non-threaded holes (5a, 5b, 5c, 5d) in the inner planes (2b 1, 2b 2) of the structural members (2a, 2b, 2c); a plurality of hollow adjustable structural members, each adjustable structural member having one square opening at the end portion of one plane thereof and a circular opening at the end portion of the opposite plane thereof; and a plurality of rectangular metal blocks, each rectangular metal block having a circular edge and two non-threaded holes (8a, 8b) on opposite walls thereof, wherein said holes are positioned at a distance "X=2Y" and said rectangular metal block is configured to facilitate the fixing of one of the adjustable structural members to the structural member (2a, 2b, 2c) or another adjustable structural member. a plurality of hollow structural members (2a, 2b, 2c), each structural member having two inner planes (2b 1, 2b 2) each with two non-threaded holes (5a, 5b, 5c, 5d) at both ends and a plurality of threaded holes arranged in between said non-threaded holes (5a, 5b, 5c, 5d), said holes positioned at a distance "Y"; a plurality of die-cast heavy duty corner modules, each corner module comprising a base cube, the base cube having an "M" threaded hole (A 3) and three rectangular block shaped protrusions (1 b, 1 c, 1 d) extending outwardly from three adjoining faces of the base cube, each rectangular block-shaped protrusion (1 b, 1 c, 1 d) having two threaded holes in each inner wall of the protrusion, wherein said holes are positioned at a distance "Y", wherein said protrusions are configured to receive the end portion of the structural members (2a, 2b, 2c), such that the structural member (2a, 2b, 2c) is slidably insertable to the protrusion and fixable together with the use of screws (3a-3f), that pass through the non-threaded holes (5a, 5b, 5c, 5d) in the inner planes (2b 1, 2b 2) of the structural members (2a, 2b, 2c); a plurality of hollow adjustable structural members, each adjustable structural member having one square opening at the end portion of one plane thereof and a circular opening at the end portion of the opposite plane thereof; and a plurality of rectangular metal blocks, each rectangular metal block having a circular edge and two non-threaded holes (8a, 8b) on opposite walls thereof, wherein said holes are positioned at a distance "X=2Y" and said rectangular metal block is configured to facilitate the fixing of one of the adjustable structural members to the structural member (2a, 2b, 2c) or another adjustable structural member.