A transition structure (20; 100) for supporting a tower on posts, comprising: a plurality of panels (26; 102) that each include: a panel body (40; 106) having opposed upper and lower ends (22, 30; 108, 110); a lower mounting surface (54; 112) at the lower end (30; 110) of the panel body (40; 106); an upper mounting surface (52; 114) at the upper end (22; 108) of the panel body (40; 106), the upper mounting surface (52; 114) being generally planar, the panel body tapering from the upper mounting surface (52; 114) to the lower mounting surface (54; 112); and a pair of lateral mounting surfaces (50; 116) at lateral edges of the panel body (40; 106), wherein each of the plurality of panels (26; 102) are mounted to at least another of the plurality of panels at corresponding lateral mounting surfaces to form, with the upper ends (22; 108) of the plurality of panels (26; 102), a shape that conforms to a lower end of the tower to be supported; the transition structure being characterised by: a plurality of footings (32; 104) each including an upper end (78; 132) mated to the lower mounting surface (54; 112) of one of the panels (26; 102), a lower end (76; 132) configured to mate with one of the posts, and a footing body (82; 138) between the upper and lower ends (54, 76; 112,132). a plurality of panels (26; 102) that each include: a panel body (40; 106) having opposed upper and lower ends (22, 30; 108, 110); a lower mounting surface (54; 112) at the lower end (30; 110) of the panel body (40; 106); an upper mounting surface (52; 114) at the upper end (22; 108) of the panel body (40; 106), the upper mounting surface (52; 114) being generally planar, the panel body tapering from the upper mounting surface (52; 114) to the lower mounting surface (54; 112); and a pair of lateral mounting surfaces (50; 116) at lateral edges of the panel body (40; 106), wherein each of the plurality of panels (26; 102) are mounted to at least another of the plurality of panels at corresponding lateral mounting surfaces to form, with the upper ends (22; 108) of the plurality of panels (26; 102), a shape that conforms to a lower end of the tower to be supported; the transition structure being characterised by: a plurality of footings (32; 104) each including an upper end (78; 132) mated to the lower mounting surface (54; 112) of one of the panels (26; 102), a lower end (76; 132) configured to mate with one of the posts, and a footing body (82; 138) between the upper and lower ends (54, 76; 112,132). a panel body (40; 106) having opposed upper and lower ends (22, 30; 108, 110); a lower mounting surface (54; 112) at the lower end (30; 110) of the panel body (40; 106); an upper mounting surface (52; 114) at the upper end (22; 108) of the panel body (40; 106), the upper mounting surface (52; 114) being generally planar, the panel body tapering from the upper mounting surface (52; 114) to the lower mounting surface (54; 112); and a pair of lateral mounting surfaces (50; 116) at lateral edges of the panel body (40; 106), wherein each of the plurality of panels (26; 102) are mounted to at least another of the plurality of panels at corresponding lateral mounting surfaces to form, with the upper ends (22; 108) of the plurality of panels (26; 102), a shape that conforms to a lower end of the tower to be supported; the transition structure being characterised by: a plurality of footings (32; 104) each including an upper end (78; 132) mated to the lower mounting surface (54; 112) of one of the panels (26; 102), a lower end (76; 132) configured to mate with one of the posts, and a footing body (82; 138) between the upper and lower ends (54, 76; 112,132).