this Cathedral survived even during the terrible blockade in the great Patriotic war. This huge Golden dome was painted over with gray paint, so as not to attract the attention of Nazi bombers with its Shine from above... in its deep cellars were hidden most of the valuable works of art (sculptures, statues), which could not be taken to the rear because of their large size. And now we see the chips and potholes on the columns of the Cathedral - as a memory of those terrible days. they are specially preserved for future generations... to all people remembered. Thanks,@tattoodjay