Saint Isaac's Cathedral is a large architectural landmark cathedral that currently functions as a museum with occasional church services in Saint Petersburg, Russia. It is dedicated to Saint Isaac of
Design model of the cathedral, 1818–1821, designed by Montferrand, wood, plaster, metal, oil paint, gilding, collection of St. Petersburg Academy of Arts
Montferrand's design of the dome is based on a supporting cast iron structure, and was only the third dome to be constructed this way