Sumela Monastery is a Greek Orthodox monastery dedicated to the Virgin Mary located at Karadağ within the Pontic Mountains, in the Maçka district of Trabzon Province in modern Turkey.
Nestled in a steep cliff at an altitude of about 1,200 metres (3,900 ft) facing the Altındere valley, it is a site of great historical and cultural significance, as well as a major tourist attraction within Altındere National Park. Due to an increase in rock falls, on 22 September 2015 the monastery was closed to the public for safety reasons for the duration of one year to resolve the problem; this was later extended to three years. It reopened to tourists 25 May 2019. The Monastery is one of the most important historic and touristic venues in Trabzon.