The Kumbh Mela at Ramghat, that happens once every 12 years is one of Ujjain's main claims to fame. Known to be the largest gathering of Hindu pilgrims, the Kumbh Mela has been recognized by the UNESCO as part of Intangible Cultural Heritage of Humanity.
An unfathomable number of Hindu devotees come together to take part in the bathing ritual that happens in the sacred river Shipra. However, we'd suggest you plan your trip in a way that you get to experience the grandeur of this festival (only once every 12 years). Interestingly, the planetary positions of the sun and Jupiter decide when Kumbh Mela is to be celebrated.