The citizens of St. Petersburg never expected to live up to seeing a cathedral bearing the name of St. Isaac of Dalmatia, the patron saint of St. Petersburg, as it took forty long years to build. The architect Montferrand displayed exceptional creativity in the construction and applied the innovations of science and technology. For example, many entertaining books now include a problem solved by the architect of cutting the piles to one level. From the excavation, where the piles were driven, they stopped pumping water, and when it rose to the desired level, the piles were cut on the water mirror. To create the statues and bas-reliefs the most up-to-date electroforming technology was used, which allowed for the first time in the history to place the several-meter high copper statues. The construction of the cathedral was photographed and it was one of the first photographs in our country. The cathedral served science even afterwards: it is known to contain Foucault's pendulum, which demonstrates the diurnal motion of the earth. Also, during blockade the cathedral cellars stored innumerable cultural and scientific treasures. This was the advice of an experienced artilleryman who was not mistaken: the Nazis used the dome of St. Isaac's Cathedral as a reference point and did not destroy it.