Which cathedral in Saint Petersburg has 112 monolithic granite columns?

Saint Isaac’s Cathedral in Saint Petersburg has 112 monolithic granite columns.

The columns form part of the cathedral’s four monumental porticoes. Many are made from single blocks of red Finnish granite and were raised using specially designed engineering equipment during the 19th-century construction project. Their scale is one of the building’s most recognizable features.

The present cathedral was designed by Auguste de Montferrand and built between 1818 and 1858. It replaced earlier churches dedicated to Saint Isaac of Dalmatia, whose feast day was associated with Peter the Great’s birth.

The cathedral’s vast dome is sheathed in gilded metal, and the interior combines stonework, painting, mosaics, and gilded decoration. It is now primarily a museum, although religious services are held there on particular occasions. The 112-column figure refers to the exterior granite columns, not every column inside the building.