City Under Construction for Massive Hindu Religious Festival

Beside India's holy rivers, a makeshift city is being built for a Hindu religious festival expected to be so vast it will be seen from space, the largest gathering in history.

Line after line of pontoon bridges span the rivers at Prayagraj, as Indian authorities prepare for 400 million pilgrims – more than the combined population of the United States and Canada – during the six-week-long Kumbh Mela.

The millennia-old sacred show of religious piety and ritual bathing is held once every 12 years at the site where the holy Ganges, Yamuna and the mythical Saraswati rivers meet.

But this edition from 13 January to 26 February is expected to be a mega draw, as it is set to coincide with a special alignment of the planets.

Beads of sweat glisten on labourer Babu Chand's forehead as he digs a trench for seemingly endless electrical cables, one of an army of workers toiling day and night at a venue sprawling over 4,000 hectares.

"So many devotees are going to come," said 48-year-old Chand who is working for a noble cause for the mela, or fair.

"I feel I am contributing my bit – what I am doing seems like a pious act."