Basilica of the National Shrine of the Assumption of the Blessed Virgin Mary

The cathedral is a monumental neoclassical-style building designed in conformity to a Latin cross basilica plan — a departure on Latrobe's part from previous American church architecture, but in keeping with longstanding European traditions of cathedral design. The plan unites two distinct elements: a domed space and a longitudinal axis. 

The principal feature of the main façade is a classical Greek portico with Ionic columns arranged in double hexastyle pattern, immediately behind which rise a pair of cylindrical towers. The exterior walls are constructed of silver-gray gneiss quarried from the Ellicott City Granodiorite.

The interior is occupied by a massive dome at the crossing of the Latin cross plan, creating a centralizing effect which contrasts the exterior impression of a linear or oblong building. Surrounding the main dome is a sophisticated system of barrel vaults and shallow, saucer-like secondary domes. The light-filled interior designed by Latrobe was striking in contrast to the dark, cavernous recesses of traditional Gothic cathedrals.

The Basilica houses many precious works of art, including two heroic portraits: the first entitled Descent from the Cross by Pierre-Narcisse Guérin and the second, by Baron Charles de Steuben, depicts Louis IX of France burying his plague-stricken troops before the siege of Tunis at the beginning of the Eighth Crusade in 1270. Both portraits were gifts of King Louis XVIII of France shortly after the 1821 opening of the Basilica.

The Basilica of the National Shrine of the Assumption of the Blessed Virgin Mary, also called the Baltimore Basilica, is a Catholic cathedral in Baltimore, Maryland. It was the first Catholic cathedral built in the United States after the nation's founding, and was among the first major religious buildings constructed therein after the adoption of the U.S. Constitution.

As a co-cathedral, it is one of the seats of the Catholic Archdiocese in Baltimore, Maryland. Additionally it is a parish church (ranked minor basilica) and national shrine. It is considered the masterpiece of Benjamin Henry Latrobe, the "Father of American Architecture".  Latrobe was America's first professionally trained architect and Thomas Jefferson's Architect of the U.S. Capitol.

Many famous events have occurred within its walls, including the funeral Mass of Charles Carroll of Carrollton, the only Catholic signatory of the Declaration of Independence. Carroll had been the last of the surviving signers. Most of the first American bishops were consecrated here to fill the ever-multiplying dioceses necessitated by the young country's territorial expansion and the great growth of the American Catholic population. Until recent years, more priests were ordained at the Baltimore Basilica than in any other church in the United States.