Once every 12 years, all the seers, saints and aspirants of spiritual knowledge congregate at the confluence (sangam), of the 3 holy rivers, Ganga, Yamuna and Saraswati. The Ganga is a symbol of Knowledge and Self-inquiry. It is on the banks of the Yamuna that events of love have been immortalized. When Knowledge and Love come together, when the head meets the heart, Saraswati, symbolic of wisdom and the fine arts emerge.
When a tiny atom explodes, the radiation lasts for a long time, the mind is even more subtle than one millionth of an atom. When the mind explodes, that is Enlightenment. Over the centuries, thousands of sages who have meditated, done penance and been enlightened come to the "Kumbha Mela" and relieve themselves of the burden of the merits gained through Sadhana by bathing in the rivers. Water has the quality to absorb the energy that they radiate. The seekers, who come from all corners to be in the company of the seers and saints, gain that merit when they take a dip in the rivers.
Space by itself cannot be bought, and a lump of clay has no value, but when space is enveloped by clay it gains value, this is a Kumbha (pot). Spirit is all over in Nature, but when it dawns in the human body as an elevated state of consciousness, then it gains immense value. An Embodied and elevated spirit is usually referred to as Kumbha. This is why the enlightened age is also called the Aquarian age. Kumbha denotes a pot, which is symbolic of fullness and perfection.
The Kumbha Mela is an ancient version of a spiritual expo.