The Russian Orthodox Church "St. Nikolay" is one of the most remarkable architectural structures in Sofia. Situated at the intersection of Rakovski Str. and Tsar Osvoboditel Blvd. the remarkable monument of Russian architecture, built between 1907 and 1914, was designed in the Russian Revival style, inspired by the Muscovite Russian churches of the 17th century. The frescoes are among the notable works of Russian artists. The church has five small gilded domes, the highest one being 19 m high. The bells were donated by Emperor Nicholas II himself.

Apart from its impressive architecture and murals, the Russian Church is extraordinarily popular because of the Blessed Archbishop Seraphim Sobolev. He was buried in the crypt. The orthodox bishop, considered a miracle worker by many, made the following promise before his death: "If I appear dauntless and selfless before the Lord, I shall not leave you." Therefore, the Orthodox tradition of writing prayer letters lives on here. For more than 50 years, believers from near and far have been leaving their letters of prayer here, hoping that their “Grandfather” Bishop Seraphim will help them. Miracles of the church that have occured throughout the ages are well documented and nurture the faith of thousands, as well as the tradition and popularity of the Russian Church.