Quebec Holy Door marks roots of faith in Canada

I am not familiar with the tradition of a Holy Door. Is this something relatively new, or is it ancient? Is it simply a spiritual artwork to be admired, or is there an indulgence attached to using it? Apparently the door will remain unlocked only until this time next year.

Quebec Archbishop Gérald Lacroix hopes the Holy Door being installed at la Basilique-cathedrale Notre-Dame de Quebec will draw more than a million North Americans closer to their roots and faith.
“The idea is not to just come to the door,” said Lacroix. “People love to go to the roots of their faith. We get over a million visitors already a year in our cathedral (and) we’ll certainly get a lot more.”*

*This Holy Door is the seventh of its kind — four can be found at the basilicas in Rome, one is in France and the other in Spain — and will open up into the Chapel of the Sacred Heart on the north side of the basilica.

The Knights of Columbus Supreme Council, the Québec State Council and the the 10 Canadian State Councils pooled $500,000 to fund the creation of the Holy Door.*
catholicregister.org/news/toronto-gta/item/17318-quebec-holy-door-marks-roots-of-faith-in-canada

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