The Trinity Lavra of St Sergius.

If you visit Moscow  note that 1,5 hours from Moscow  by  local train you can find very interesting place - The Trinity Lavra of St. Sergius ( Тро́ице-Се́ргиева Ла́вра)  in the city called Sergiev Posad ( Сергиев Посад) 


This is the most important Russianmonastery and the spiritual centre of the Russian Orthodox Church. 

The monastery was founded in 1337 by one of the most venerated Russian saints, Sergius of Radonezh, who built a wooden church in honour of the Holy Trinity on Makovets Hill.

You can visit official site of  Lavra and read more  ( in different languages)