The Serpukhov Kremlin was constructed in 1556 on the orders of Grand Prince Vasili III of Moscow to protect Moscow's southern borders from Crimean Tatar raids. Once the Crimean threat was eradicated the Kremlin slowly fell into disrepair. Even by the 19th century it was considered ruins and its stone was taken for local needs. The final blow was dealt in 1934 when the Bolsheviks decided to use the remainder of the Kremlin's stone as building material for the Moscow Metro. Now only a small fragment remains on Ulitsa Krasnaya Gora.

Trinity Cathedral

Inside the Kremlin at the top of Sobornaya Gora is the Trinity Cathedral, which was built in 1696 to replace an earlier church which once stood on this spot. The cathedral is an example of Moscow baroque and is the standard "octagon on a cube" construction joined with a bell tower. Near to the church are the foundations of the St Nicholas' Cathedral, which once stood here, as well as a war memorial.