Abstract: Unit panels for constructing tanks and tanks so constructed. The panels include a rectangular plate and four connecting rims. The connecting rims are provided on the four sides of the rectangular plate and extend in the same direction with respect thereto. The forward ends, or edges, of the connecting rims define a flat plane which is perpendicular with respect to the connecting rims; the rectangular plate being inclined with respect to the flat plane and at least two of the connecting rims have rectangular shapes.Various embodiments of the unit panels are provided and include panels wherein two opposing connecting rims are rectangular, the remaining opposing rims being trapezoidal; panels wherein two adjacent connecting rims are rectangular, the remaining adjacent rims being trapezoidal; and panels wherein the rectangular plate is recessed or projections extending in a direction opposite to that of the connecting rims are provided on the rectangular plate.