The site of the building originally housed the neo-Gothic monastery complex of the Sisters of Our Lady of Mercy, which was designed by Charles Zaremba and was built between 1889–1891. In 1966, the remains of Sister Faustina were moved to the church. In 1968 Cardinal Karol Wojtyła designated the church as a shrine, thanks to the remains of Sister Faustina. In 1985, Pope John Paul II called Lagiewniki the "capital of the Divine Mercy devotion". Since the beatification of Saint Faustina in 1993, her remains rest on the altar, below the image of Divine Mercy.
In 1999–2002, a modern two-story, ellipsoidal basilica, specifically devoted to the Divine Mercy was built. The building was designed to resemble a boat, and has a 77-meter high observation tower that resembles a mast. The basilica can accommodate about 5,000 people and the main chapel has about 1,800 seats. The altar in the main sanctuary houses the Divine Mercy painting and relics of Saint Faustina. The image above the main altar was painted by Adolph Hyla in 1944, and replaces the first image Hyla painted in 1943 as a votive offering for surviving during World War II. The image and the basilica are a major pilgrimage site and in 2011 the basilica received around 2 million pilgrims from around the world. The lower level of the church has a central a chapel dedicated to Saint Faustina, with four side chapels. The upper part of the basilica has free-standing post-modern Chapel of Perpetual Adoration of the Blessed Sacrament. On June 24, 2007, on the 60th anniversary of Operation Vistula, the Basilica opened a Greek Catholic chapel dedicated to reconciliation, and as a gift to the Greek Catholic Church.
Report of miracle
In March 1981, while praying at the tomb of St. Faustina at the church, Maureen Digan of Massachusetts reported a healing. Digan had suffered from lymphedema for decades, and had undergone 10 operations, including a leg amputation. Digan reported that while praying at Faustina's tomb she heard a voice saying "ask for my help and I will help you" and her constant pain stopped. Upon her return to the US, five Boston area physicians stated that she was healed. Digan's healing was declared miraculous by the Vatican in 1992, and paved the way for the beatification of Faustina Kowalska.
Papal visits
On June 17, 1997 PopeJohn Paul II visited the church to pray at the tomb of Saint Faustina - an event commemorated by a relief at the entrance to the chapel. In May 2006, Benedict XVI visited the chapel, and a second relief commemorates that. During the 2006 pilgrimage by Pope Benedict XVI, he unveiled a statue of Pope John Paul II at the observation tower at the basilica, as the seventh sculpture of John Paul II in Kraków. In July 2016, Pope Francis visited the Basilica as part of the Jubilee Year of Mercy and as part of the InternationalWorld Youth Day celebrations taking place in Kraków.
