Pilgrims gather for Kumbh Mela

Pilgrims are beginning to converge on the northern Indian town of Allahabad for the most important spiritual gathering in Hinduism, the Kumbh Mela.

This highly sacred event, during which devotees bathe in the Ganges, only takes place once every twelve years. The Kumbh is held at the confluence of three rivers, and Hindu scriptures say that this is one of four places on which the Gods spilt a drop of the elixir of immortality. Fifteen-million people -- the largest ever gathering in human history -- attended the last Kumbh, and more are expected this time.

To cater for the expected multitude, the authorities have been struggling to build a vast temporary infrastructure.

Dozens of roads and a pontoon bridge have been constructed, along with a special hospital, fire stations and police posts. A labyrinth of water and sewage pipes and electrical cables have been laid.

And hundreds of trains and buses have been organised in an attempt to ease the massive congestion surrounding the Kumbh.

From the newsroom of the BBC World Service