On Red Square, you can see the black pyramid with the word: ЛЕНИН . This is Lenin’s mausoleum, and simply for the experience, you can go check out his preserved body in a glass case inside the pyramid. Per legend, Lenin’s body didn’t begin to decay like normal bodies, just as saints’ bodies do not decay, and thus it was concluded perhaps he was somewhat of a saint and the decision was made to artificially continue this preservation. Visiting is free, but you need to queue up. The hours change depending on the season and the week. It’s an odd experience, and most Russians I know have not actually been to see his body and periodically there are movements to stop funding the preservation of his body and to close the whole thing down.
However, you can still visit Lenin’s body. So, wait in line, go through metal detectors, and walk, in silence, looking at all the Soviet leader’s graves (Stalin is there, and some others) which line the Kremlin wall and are hidden from sight if you’re just standing on Red Square. Once inside the mausoleum, you’re expected to keep moving and maintain a reverent quiet. There are guards posted to ensure this. Lenin is there, in a glass box, lying there with his eyes closed. (One hand covers the other, apparently because one hand started to show signs of decay.)