The monolith itself took 14 years to carve. Vigeland never explained the meaning of this monolith, but some of the people it depicts are helping others to climb up, while some are struggling not to fall, and others are ambivalent or sitting toward the top without care for others. So my best interpretation is that this is the world we live in: we humans are forced together often in close proximity, and this monolith depicts the wide range of ways people behave when forced together.