Basilica of the National Shrine of the Immaculate Conception

Construction of the basilica began in 1920 and proceeded in multiple phases through the mid-20th century; it was dedicated in 1959 and remains primarily Neo-Byzantine in architectural character. It is the largest Roman Catholic church in the United States and features extensive interior mosaics, including the prominent Trinity Dome mosaic. The building serves as both a minor basilica and the national shrine for the United States.