Listers, SPL presents the National Shrine of the Immaculate Conception and its gorgeous Romanesque-Byzantine architecture.

National Shrine of the Immaculate Conception Virtual Galleries:
Upper Church Tour
Lower Crypt Church Tour
360 Virtual Tours

In their own words:

The Basilica of the National Shrine of the Immaculate Conception is neither imitative nor duplicative of any other church in the world. Its architecture is Romanesque-Byzantine in style and its construction is entirely of stone, brick, tile and mortar—without steel structural beams, framework or columns.

Romanesque architecture is defined by its massive size, thick walls, arches, piers, groin vaults, towers and ornamented ambulatories. The form of the structure is clearly defined and symmetrical. In comparison to Gothic structures, a Romanesque church is quite simple in appearance.

Byzantine architecture in the West was superseded by that of the Romanesque style. The dome is the dominant feature in Byzantine architecture and is one of the great advances in church architecture fostered by the Byzantine style. A circular or elliptical dome was placed over a square or rectangular room by means of pendentives, the triangular construction of which strengthened and supported the base that holds the dome.

More from the official site:

The Basilica of the National Shrine of the Immaculate Conception contains the world’s largest collection of contemporary ecclesiastical art.

The Basilica’s artistic embellishment, both inside and out, is in keeping with the Romanesque-Byzantine style of its architecture.

Romanesque art is very enthusiastic in its use of figurative or stone sculpting. The exterior of the Basilica contains both heroic size figures of saints and finely sculpted tympana and archways. Tympana sculpted in relief ornament the interior east and west entrances and various niches in the nave and chancel areas. Stained and faceted glass windows decorate both the Upper and Lower Church areas.

Byzantine art is remarkable in its use of mosaic and marble. Above the spring line, this includes the mosaic ornamentation of the seven main domes along the many side chapels and oratories. The current calculation of the mosaic interior of the Basilica is 75,545 sq. ft. Below the spring line, the church is adorned with beautiful marble claddings. The finer marbles open out allowing the marble veining to form symmetrical patterns.

The brilliant mosaics, stained glass windows, and polished stone carvings throughout the Basilica, and in its more than 70 Chapels and Oratories, express the reality of God dwelling with us.

Dominating the North Apse of the Great Upper Church is the Byzantine style mosaic Christ in Majesty. It is one of the largest mosaic images of Jesus Christ in the world and contains more than 4000 shades and colors. Other mosaic images depict the Creation of the World, the Incarnation, Redemption, the Outpouring of the Holy Spirit at Pentecost, and the Last Judgment.

The Basilica’s Crypt Church is modeled after the Early Christian Catacombs. Its characteristic Roman arches are supported by 10-ton granite columns and form two Guastavino tile domes, which are complemented by the unique ceramic artistry of Mary Chase Stratton. While Guastavino (Catalan) vaulting and Mary Chase Stratton (Pewabic) ceramics are featured independently in structures throughout the United States, even in the U.S. Capitol, it is only at the Basilica of the National Shrine of the Immaculate Conception where these two artists and art forms found their unique artistic expression in concert with each other.