In the construction of a land-based skirt-supported spherical tank, the tank is partially prefabricated, its bottom polar cup section being produced ready for mounting and stored inside the rest of the spherical shell. In this state, wherein the transportation height of the tank has been substantially reduced, the as yet unfinished spherical tank is transported to the erection site, where the bottom polar cap section is lowered into position and secured to the rest of the spherical shell. A particular advantage of using spherical tanks as storage tanks is their safety and operational reliability. Very good experience has been gained with such tanks from maritime applications. A special advantage is that extensive insulation is not required between the tank support and the ground, as is the case if large upright cylindrical tanks with flat bottoms are utilized. During transportation, the prefabricated structure is preferably supported by a temporary support structure in the region which later will become the skirt region. This temporary support structure can be removed when the permanent skirt is constructed at the installation site, or the temporary structure may become part of the permanent skirt