The Basilica of the National Shrine of the Immaculate Conception is a Roman Catholic basilica located in Washington, D.C., United States. It is the largest Roman Catholic church in North America and a popular tourist destination. The basilica was dedicated in 1959 and is considered one of the finest examples of neo-Byzantine architecture in the world.

The Basilica is dedicated to the Immaculate Conception, a Catholic doctrine that states that the Virgin Mary was conceived without original sin. The church is open to visitors of all faiths and is a place of pilgrimage for Catholics from all over the world.

The interior of the basilica is adorned with beautiful mosaics, stained glass windows, and intricate marble sculptures. The main altar is made of white marble and features a mosaic of the Immaculate Conception. The basilica also contains the Chapel of Our Lady of the Blessed Sacrament, which features a collection of relics and a beautiful stained glass window.