Chanting verses from the Islamic holy book, millions of Muslim pilgrims crammed into buses, trains and river ferries to attend one of the world's largest mass prayer sessions at a riverbank outside the Bangladeshi capital Sunday.
Many walked from far-flung villages to attend the Akheri Munajat, or final prayer session, which wraps up a three-day Islamic congregation.
Up to 4 million Muslims are expected to participate in the mass prayer, organizers said. Bangladesh's prime minister and president were also expected to attend, their offices said.
Known as Biswa Ijtema, or world congregation of Muslims, the annual gathering is dedicated to teaching the tenets of Islam, and shuns politics.
It started in 1966 as a small gathering of Islamic scholars and preachers meeting at a mosque in the capital, Dhaka. But as its popularity grew - attracting thousands of devotees - the event was moved to the riverbank at Tongi, an industrial town 12 miles to the north.
During this year's assembly, the devotees from across Bangladesh - and from neighboring countries like India and Pakistan - prayed together and listened to scholars give sermons on Islamic principles and discussed the Islamic holy book, the Quran.
Seeking to relive the simplicity of Islam in its early days, the pilgrims also carried supplies and cooked their own food. They slept in hundreds of tents that were erected on nearly 160 acres of land on the riverbank.
Following Islamic tradition, women devotees were not allowed inside the main venue, but they camped separately in nearby villages.
Meanwhile, nearly 10,000 people - from farmers to university lecturers - have volunteered to go out in groups for a few weeks and preach the basics of Islam.
"Islam is a religion of peace, charity and simplicity," said Maulana Azizullah, a spokesman for the congregation. "We work to spread this message."
The event is organized by Tablig Jamaat, an organization of Islamic preachers based in New Delhi, India.