"I was speechless. My spine tingled as surely I was witnessing one of humanity's great mass events. How had I never heard of this? I was caught between wanting to capture what was before my eyes but also not to miss absorbing what I was witnessing. After a few minutes the praying was over, there was then a minute's silence to remember all the Muslim people lost since the last Bishwa Ijtema, then the people returned to their cars, buses, rickshaws, returned to their shopping, returned to the congress. The horns started blaring and the traffic took back over its rightful ownership of the roads. That was it over, but it's 5 minutes that will stick with me forever."

Every year, a very large Muslim congress takes place, the Bishwa Ijtema (“world gathering”), the second largest Muslim congregation after the Hajj pilgrimage. It is usually held in January, but In 2019, when Adrian visited the country, the Bangladesh national elections were to be held in January. At the last minute the government directed the Bishwa Ijtema organisers to reschedule the 2019 assembly to February, providing Adrian the opportunity to witness this extraordinary event as a spectator. “It was just spine tingling to witness. Truly one of humanity's most amazing events. I would say it is akin to the great migrations in Africa,” he says. There are large tent compounds that are fenced off to non Muslim people, but Adrian could see into these from nearby footbridges. This is not a festival of dance and celebration but to discuss the tenets of Islam.

An ijtema is one of the regularly scheduled events organised by the Tablighi Jamaat. It is the annual gathering of followers, which is held at the Tablighi headquarters in various countries. Tablighi Jamaat is an orthodox Islamic movement that focuses on practising the religion as it was practised during the lifetime of the Islamic prophet Muhammad and on spreading the faith. Established in India in 1926, it began as a response to a perceived deterioration of moral values and an alleged neglect of the traditional aspects of Islam. The movement is still headquartered at Nizamuddin Markaz in South Delhi, India.

The Tablighi Jamaat adherents are said to be non-political, and the organisation's representatives strictly avoid political activities and debates and instead focus on religion. As such it is also seen by some as a counterpoint to several political Islam movements. The Tablighi teachings are in accordance with Sunni Islam, the largest denomination of Islam, followed by 87–90% of the world's Muslims, which is characterised by a greater emphasis on the traditions of the Prophet Muhammad (the word Sunnah refers to the behaviour of the Prophet).

According to the Tablighi ideas, the promotion of dawah (proselytising Islam, or missionary work) is a mechanism of self-reform and does not require the highest standards of Islamic scholarship. All Muslims, according to this, are expected to engage in dawah and should adopt - and invite others to - the Islamic lifestyle, which follows a strict code of conduct and dress. The Tablighi are in effect missionaries wanting to propagate a traditional Islamic way of life by peaceful means, teaching and encouraging others through personal engagement, such as preaching.

After India was partitioned in 1947, the Tablighi movement expanded within South Asia with a Pakistan Chapter. This remained the largest chapter until Bangladesh became independent from Pakistan in 1971. The movement now has a worldwide presence, including in Europe and the United States. Since the movement is relatively loosely organised and there is no formal 'membership registration' process, the exact follower numbers are unknown. Estimates of current adherents range from between 12 to 80 million across more than 150 countries.

A typical ijtema, such as the one witnessed by Adrian, continues for three days and ends with an exceptionally long prayer. Millions of Muslims congregate for four days on the outskirts of Dhaka, living in tent cities, to pray and to listen to scholars recite from the Qur'an and explain the meaning of verses. During the Bishwa Ijtema all the mosques are so full that millions of people move out onto the streets to pray, halting the seemingly endless gridlocked traffic.

In Bangladesh, where Adrian was able to observe the annual Bishwa Ijtema in 2019, the largest of such annual gatherings is held. More than 3 million people congregate at the Bengali meeting near the capital Dhaka. Speakers include Islamic scholars from various countries. Millions of devotees come to discuss religion and strengthen their faith and to receive new impetus for their missionary zeal.

The congregation takes place in an area spanning over five square kilometres in Tongi, an outer suburb north of Dhaka. Bangladesh, with one of the world's largest Muslim population, also has one of the world's poorest populations, with most of its people dependent on public transport to travel. Buses, trains, boats arrive and depart completely overloaded with thousands and thousands of people, packed inside and out. Many travel on foot. The roads are jammed for many kilometres.