Visible from much of the city due to its location at the top of Nikolskaya Hill is the Svyato-Troitse Nikolsky Monastery which is also simply known as the Nikolsky Monastery. Previously a wooden fortress stood here from the time the city was first founded. The monastery was established in the first half of the 17th century and its main cathedral - the Trinity Cathedral - was built between 1681 and 1689. This was joined by the smaller St John Climacus' Church in 1716. Stone walls were added in the 18th century, complete with the Intercession Gate-Church. In the 1920s the monastery was closed and its buildings were converted into housing. In the process parts of the walls including the Intercession Gate-Church were demolished. In 1993 the monastery was returned to the Orthodox Church and restored. Close to the monastery at the bottom of Nikolskaya Hill are two wooden chapels one holding a holy spring and one holding a large font which has separate sections for men and women.