In recent years, there has been an ex-traordinary intensification of pilgrimage practices, which has translated into the need of larger and more frequently constructed urban structures for hosting massive gatherings. The case of the Kumbh Mela, a legendary Hindu festival in India, sets the standards for understanding alternative ways of building cities that are transitory and with a temporality aligned with the ephemeral nature of massive human flows. This massive cultural gathering, resulting in the biggest ephemeral mega city in the world accommodating 3 million pilgrims every 72 years, generates an extreme case that forces us to reflect deeply about the way we may think of future cities more broadly and from which we can extrapolate several lessons regarding more resilient, open concept-of architecture, urban design and planning policy.