Sikhs celebrate founder Guru Nanak's 550th birth anniversary
It is one of the biggest birthday celebrations in the world: millions of Sikhs will today mark the 550th birth anniversary of Guru Nanak, the founder of their religion.
In pictures: Pakistan welcomes scores of Sikh pilgrims to Gurdwara Darbar Sahib in landmark ceremony
The annual celebration has been given extra significance this year with the opening of the Kartarpur Corridor, a secure, visa-free passage between India and Pakistan that gives Indian Sikhs access to the place where the guru breathed his last in 1539, now one of the religion's holiest sites.
What is Sikhism?
Sikhism is a monotheistic religion born in the 15th-century in Punjab — meaning the land of five rivers, a region spanning parts of what is now India and Pakistan.
Five and a half centuries later, Sikhs number up to 30 million worldwide, with a rich diaspora in places such as Canada, the US and Europe — although the vast majority remain in India.