Sikhs from all over the world have begun arriving in the holy city of Amritsar, northern India, to commemorate the 400th year of the Sikh holy book, the Guru Granth Sahib, on 1 September.
By Asit Jolly
BBC correspondent in Chandigarh
The Golden Temple has been lit up for the event
The holiest Sikh shrine, the Golden Temple, will be the centre of celebrations that are expected to attract more than 4m visitors to Amritsar, in the northern state of Punjab.
There is a distinct air of festivity in Amritsar's Old City, which surrounds the Golden Temple, also known as Harimandir Sahib - a site as sacred to Sikhs as Mecca is to Muslims.
1 September 2004 has a special significance for the Sikhs.
It was on this day, exactly 400 years ago, that the Guru Granth Sahib - a textual compilation of the teachings of the Sikh Gurus - was brought to the Golden Temple by the fifth Sikh guru, Guru Arjan Dev.
The Guru Granth Sahib is the source of spiritual guidance to all Sikhs.
Sikh men march in the run-up to the ceremony
It is revered as a symbolic representation of the 10 Sikh Gurus and is accorded the same respect that would have been given to any of the Gurus themselves.
Amritsar has been gearing up for the celebrations.
The Old City has been given a fresh coat of paint and roads and lanes leading to the Golden Temple have been covered in new carpets.
Special arrangements are being put in place to receive, what city officials estimate will be the biggest influx of visitors to Amritsar ever.
More than 4m devotees are expected to arrive during the five-day celebrations with the biggest influx expected on Wednesday.
Seminars and speeches
The religious body responsible for the upkeep of Sikh shrines, the Shiromani Gurudwara Prabandhak Committee or SGPC, and the Punjab government are doing everything possible to make the celebration a memorable affair.
A festive atmosphere is evident on the spruced-up streets of Amritsar
Special commemorative gold and silver coins are being issued.
The Golden Temple and the surrounding complex of buildings have been covered with decorative lighting and there are plans for a spectacular fireworks and laser display.
There will also be a seminar on the philosophy of the Guru Granth Sahib, an exhibition of religious paintings and religious artefacts, and a massive public congregation, which is expected to be addressed by several religious and political leaders including India's Prime Minister, Manmohan Singh.
More than 7,000 police have been deployed in Amritsar City.