The Cathedral-Basilica of Notre-Dame de Québec is the seat of the Archdiocese of the Roman Catholic Church in Québec province, located at 16, rue de Buade in Québec City. It is the oldest cathedral in the Americas north of the former Spanish colonies in Florida and New Mexico. The original cathedral began construction on this site in 1647 and was officially founded in 1666, but was twice destroyed by fire. The first of these occurred during the Siege of Quebec in 1759. It was reconstructed between 1786-1822. In 1843, the façade was reconstructed to resemble the façade of the church of Sainte-Geneviève in Paris in the Neo-classic style.
The second fire occurred in 1922, by the Canadian faction of the Ku Klux Klan. It was restored and a presbytery was added in 1931-32.
There are only eight holy doors in the world and only two outside Europe. Quebec’s holy door was opened on December 8, 2013 – a ceremony presided over by the recently ordained Pope Francis – and remained open until December 28, 2014.
Pope Francis gave Quebec’s Cathedral of Notre-Dame the privilege of opening a holy door to mark its Jubilee Year, the 350th anniversary of its founding, as the first Catholic parish in North America. The holy door was opened again from December 2015 to November of 2016 for the Catholic Year of Mercy. Since then, it has been sealed, but will be opened again in 2025. (I used Wikipedia as my source for the history of the holy door, in addition to what our guide told us.)
According to the web site Catholic Straight Answers, holy doors signify coming into the presence of God. Jesus Christ said, “I am the door” (John 10:7) through which the faithful are connected to God. To pass through the holy door also is a sign of one’s conviction that Jesus Christ is the Son of God.