As completed the cathedral is surmounted by a single dome on a high
drum, with two double-tiered bell towers on either side of the
loggia of the central entrance. The main entrance consists of a portico of six
Doric columns, with the facades consisting of shallow panels and
pilasters. The north and south entrances are surmounted by
bas-relief panels sculpted by
Fedot Shubin, depicting events from the Old and New Testaments. The cathedral occupies a cruciform floor plan, with three
naves. The main nave is supported by
Corinthian columns, while the drum of the dome contains 16 windows. The
iconostasis is made of marble, with images by
Johann Jacob Mettenleiter and
Ivan Akimov and bronze detailing by . The cathedral interior was richly decorated with paintings, bas-reliefs and statues. Sculptor Fedot Shubin produced twenty bas-reliefs and statues of saints, while the
altarpiece was by
Anton Raphael Mengs. The original paintings were by Fyodor Danilov, though in 1806 Antonio della Giacomo replaced them using the sketches of
Giacomo Quarenghi. The sculpting was entrusted to F. Lamoni and
Giovanni Maria Fontana. A portrait of Catherine II by
Dmitry Levitzky hung above the royal pew; on the opposite side hung a portrait of
Peter the Great. In 1794 Catherine II donated several valuable paintings by
Peter Paul Rubens (Resurrection of Christ),
Anthony van Dyck (Blessing of the Saviour),
Jacob Jordaens (Lamentation),
Jacopo Bassano,
Guercino,
Bernardo Strozzi and others from the
Hermitage. She also later presented the church with a massive silver chandelier weighing about 13 pounds. Various relics and ornamental artefacts were collected in the cathedral, including the silver tomb of Alexander Nevsky, a piece of the
Lord's Robe, and the image of the
Theotokos of Vladimir. The cathedral underwent several restorations during its existence, though its interiors remained largely as they were originally. The arches were repainted in 1862 by P. S. Titov, according to the sketches of Academician
Fedor Solntsev. In 1847 a heating system was installed to allow the cathedral to operate in the winter. In 1862, a malachite canopy made in 1827–1828 in the Paris workshop of
Pierre-Philippe Thomire was transferred to the cathedral from the
Tauride Palace. Fifteen years later, a massive silver tomb was made under the shroud. In 1904, the main altar was lined with silver reliefs. ==Soviet period==