It took 40 years to build the cathedral. Three years after the construction had started it came to a halt because of a number of mistakes made in the project and during the building process. A special commission of notable Russian architects was formed. In 1825 the construction works were resumed according to the corrected project. Lots of complicated engineering problems were to be solved for the first time in history.
In 1828, even before the walls were erected, installation of the 48 monolithic columns was started, that were to form the porticoes, each weighing 114 tons, massive marble carved from solid marble monoliths corresponds exactly to the dramatic history of the Cathedral. The ideas of Betancourt, an engineer, made it possible to raise the 67-ton granite columns to the height of 40 m and install them around the dome drum. It was reconstructed as many as four times, has sustained a destructive fire, disastrous floods of the Neva River and a no less damaging incompetence of many architects.
The majestic grandiose cathedral strikes itself riches and luxury. The high walls inside the Cathedral are covered with various kinds of marble and porphyry, the icons are adorned with green malachite, azurite and guilt bronze. It was spent more then 400 kilograms of pure gold (of which only 100 kg of gold were used for gilding dome), 1000 tons of bronze and many others Russian semi- precious stones. 112 massive granite columns (made of single pieces of red granite) surround the cathedral, 24 statues encircle the dome. They are copies of Antique originals by J.Hermann. The Cathedral has 4 smaller bell towers, and sculptural groups of angels with torches, which adorn each corner of the Cathedral's roof. Four enormous porticoes are decorated with monolithic granite columns, brought by sea from Vyborg.
St.Isaac's Cathedral is one of the largest domed structures in the world, and nowadays is the 4th highest cathedral in the world after the world-known St.Peter's in Rome, St.Paul's in London and Santa Maria del Fiore in Florence. Having the area of 4000 square meters, the Cathedral can accommodate up to 14000 standing worshipers at a time. The dome is of an original construction, practically including three domes, placed one over other. The Cathedral astounds with its dimensions: its length is 115,5 m; width - 97,6 m. The long spiral staircase leading up in 562 steps to more than is 101,5 meters height of the balustrade of the dome is open for anyone who is able to ascend it. The walls are 5 meters thick.
Both inside and outside the cathedral is decorated with sculptures. About 400 meters high sculptural work was created by Vitali, Klod, Pimenov, Loganovsky. It was for the first time that the galvanoplastics method developed by Yakoby was used for making monumental sculptures.
The cathedral, faced with light-gray marble from Olonetsk, was completed by 1842; however, it took 16 years more to decorate the interior. A lot of valuable materials were used, among them lazurite, malachite, porphyry, all kinds of marbles. The decor of the Cathedral is extremely impressive. It is decorated with 382 works of art: sculpture, painting, mosaic. The walls and vaults of the cathedral bear paintings and mosaic works made by well-known Russian artists: Briullov, Bruni, Basin, Shebuyev and others. The mosaic has 14 sorts of marble of contrasting colors, that is 12000 shades and colors. The great plafond of the big dome with the area of more than 700 square meters was painted by Briullov. It shows Madonna surrounded by saints and angels. There's a statue of Montferrand holding a model of the cathedral and made of different colored marbles and other minerals on the west facade. The Iconostasis is decorated with ten malachite and two azurite columns; two lower tiers are mosaics while the upper tier is painted. A group of the most talented painters: Bruni, Neff, Steuben, Mussini painted the monumental murals. Also of note are the intricately sculpted bronze doors. The interiors dazzle the eye with mosaic icons, paintings and columns made of malachite and lapis lazuli. The white marble central iconostasis with its columns of malachite and lazurite, and the huge brightly colored stained glass window of the "The Resurrection of Christ" in Catholic colors (Orthodoxy has Christ wearing blue). A series of documents, plans, engravings, and models serves as an exhibition of the building of the cathedral.
But St.Isaac's was once the main Russian Orthodox Cathedral. The cathedral that stands out for its grandeur was sanctified in 1858 and became the main church in Saint-Petersburg. In the late 1920s the church was closed for services and used for an exhibition of revolutionary propaganda. It was badly damaged at the time of World War II.
In the Soviet epoch the Socialist government officials were close to demolish the dome for it blocked up the view at the Neva out of their windows. The enormous golden dome of the Cathedral brought about most complicated technical problems for the builders and especially for the painters many of who died of mercury fumes while gilding it. Since 1970 the staff of the St.Isaac's Cathedral has managed the church. The spiritual monument was under restoration for over 25 years. Nowadays with scaffoldings removed, the bell-tower dome gilded and the interiors carefully restored, the church is in its stunning beauty and it is used for services on Easter and Christmas. Since 1990, after a 62-year gap, services have been held in the cathedral on major religious holidays. Today, church services are held here only on major ecclesiastical occasions.
St.Isaac's Cathedral is a remarkable monument of Russian architecture. This grand structure filled up the space of the Senate Square, and created a new square as well. Alongside with the Peter and Paul's Cathedral and the Admiralty it became an important architectural landmark in the city outline. The golden dome of St.Isaac's can be seen from any part of the city, and in clear weather - even from the suburbs.
Before Montferrand died two years after the cathedral was completed he had conceived a monument to the iron-willed and notoriously despotic Russian ruler Nicolas I to be established in the middle of the St.Isaac Square in 1859, four years after the Emperor had died. The monument to Nicholas I accurately and powerfully depicts the determined absolutist Russian ruler as a powerful military figure.
In fact, Nicholas I was a junior army officer at heart. He was especially devoted to his troops and intricately involved in the details of the military from ordering the alteration of military uniforms to specializing in the engineering of military fortresses. His despotic rule over Russia from 1825-1855 saw the crushing of the liberal Decembrist revolt and the expanse of Russian territory largely at the expense of Turkey.
Several different sculptures were used in creating the monument. A large model of the pony which Nicholas I sits on was completed by famous Russian classical sculpture Peter Klodt. Ramazanov and Zaleman sculpted the model of the monument's pedestal. Zaleman also sculpted the four allegorical female figures, steel fixtures and ornaments on the pedestal and bas-relief showing the historic and significant "Delivery of the Codification of Law to Count Michael Speransky". It was largely through the work of Speransky and his associates that the new code was introduced during Nicholas I's reign in January 1835 marking a milestone in Russian jurisprudence.
The graceful silhouette of the equestrian rests on a grand pedestal adorned with elaborate decoration, such as historical scenes of the Nicolas's reign and the allegoric images of Justice, Belief, Wisdom and Power which bears strong resemblance with the Emperor's wife and three daughters. The statue was casually located in a line with the Bronze Horseman, the monument to Peter the Great on the Senat Square. The two monuments looked as if one statue was chasing the other and only the Isaac Cathedral got in its way. People say that several days after the monument was established a board with inscription "you'll never catch me up" was hung on its horse's right leg.
Klodt completed the casting of the pony statue and two bas-reliefs in the Liteinoy artist's studio of the Academy of Arts. A local factory completed the remaining bronze parts of the monument.
The impressive pedestal stands on a short platform made of red Finnish granite with three steps. The lower part of the pedestal is made of dark gray granite and red porphyry. The middle part is decorated with bronze bas-reliefs and hewed from red Finnish granite. The upper part of the pedestal is made of red porphyry. The pedestal of the pony statue is sculpted from white Italian marble.
The monument has an especially beautiful silhouette, but at the same time boasts a complex composition. The placement of the monument on one of the city's most beautiful and historic squares and the great interrelationship between the monument and the square is especially powerful and gives the impression of a unified and complete ensemble. Thanks to its unique construction (the horse stands on its hinds legs) the monument to Nicholas was spared during the various phases of Soviet de-tsarization despite its inherent policital-incorrectness.
The cathedral sits on the northern side of St.Isaac's Square. Opposite the cathedral is the Mariinsky Palace, home of the St.Petersburg Duma.