Serpukhov is an old Russian town in Moscow region, which stays on Oka river.
Serpukhov had a citadel (called Kremlin, like the Moscow one), which was ruined in 19th century. Now only a hill with two small fragments of a wall remains; in several places limestone bases of several towers could be seen.
Serpuknov has 3 cloisters, several churches and cathedrals.