Saint Isaac's Cathedral took forty years to build. Entrusted to the French architect Auguste de Montferrand and constructed between 1818 and 1858, it required engineering on a scale rarely attempted: monolithic granite columns quarried, transported and raised into place for the four porticoes, and a dome sheathed in gold that has anchored the Saint Petersburg skyline ever since. The interior is a display of imperial resources, with mosaics replacing paintings, columns of malachite and lapis lazuli framing the sanctuary, and sculpture throughout. Long used as a museum, the cathedral also offers a colonnade walkway around the drum with one of the finest views over the city and the Neva. Filmed in 4K, the programme follows the building from the square to the dome and tells the story of its construction.
