Gurdwara Darbar Sahib Kartarpur, where Guru Nanak Dev Ji spent his last eighteen years and died, is four and a half kilometres inside Pakistan, on the Ravi. From the Indian side at Dera Baba Nanak it is visible across the fields, and pilgrims used binoculars mounted on a platform to look at it for seventy years.
The corridor opened on 9 November 2019, before the 550th birth anniversary. Indian pilgrims can cross in the morning without a visa, spend the day, and come back. Registration and a fee are required.
It is the only visa-free arrangement of its kind between the two countries and it was agreed and built in about a year at a time when relations were otherwise at their worst in decades.
It has been closed at various points, for the pandemic and for political reasons, and reopened.
That a demand of ordinary Punjabis on both sides produced this when nothing else did is the fact worth holding on to about it.
The agreement was signed in October 2019 and provides for up to five thousand Indian pilgrims a day, without a visa, on payment of a service fee, returning the same evening.
The actual numbers have been far below the ceiling. Registration, the fee, and the political weather between the two countries have all limited it.
It is the only arrangement of its kind anywhere on this border, and it exists because both governments found a religious anniversary they could each present as a concession from the other.