I'd love to make a series of Moscow temples of all religions one day in my life. Still, since we are closer to the Polar circle than the overwhelming majority of the World, the light presently isn't much suggestive :) We are entering what I call a Polar winter :)
However, there is one item in Russia much more copious than in the rest of the countries taken together, :) and that is naturally the Russian Orthodox Churches with their peculiar architectural outlook whatever style they belong.
Now the Russian Orthodox Christians enjoy what the time and the 20th century multiple outrages of cruel violence have spared of all the wealth of churches and cathederals ever built here. The churches happened to be the first ones to accept a coup. Subjectively I estimate the number of what is left as 20% of what has ever actually existed in Moscow at all times.
Opposite of the Kremlin, across the Moskva river-Moskva-reka.
Zamoskvorechye where I presently live is the region of Moscow situated across the Moskva river: beyond the Moskva river, literally. I has always been famous with its old and rich churches.
A curious fact: in the early 20th century the majority of Moscow land belonged to the church, so presently the city faces some collision ;) since the land in Moscow is among the most expensive in the world after Tokyo, London, New York and Paris. However the lamentable condition of the majority of survived churches is obvious.