A recently-discovered chapel that doubled as a watchtower at the Sümela Monastery in Turkey's northeast Trabzon province has opened to visitors, providing new insight into the 1,600-year history of the ancient site.

The structure, termed the "Observation Chapel," is believed to have served a dual purpose both as a place of worship for monks and also a lookout post to protect the winding roads leading up the monastery from attack.

The chapel was built like a "hawk's nest," accessible only through a hidden stairway leading up to the chapel, which is raised four meters from the ground. Believed to have been constructed in the 8th or 9th century, the chapel was hidden from view by trees.

"The presence of the chapel, which overlooks Sümela from the opposite slopes in the south-east, suggests that there were small chapels and watchtowers in the area before the Sümela Monastery complex was established," Karadeniz Technical University (KTÜ) professor İsmail Köse told Ihlas News Agency.

These small outposts were most likely critical in the development of the monastery, Köse points out:

"Without the modern roads used today, it would have been unthinkable to build the monastery on the side of the mountain in the 4th century. Moreover, at that time, it would take at least a week to reach the region of Trabzon where Sümela is located."

The Observation Chapel is also believed to have been part of a communication system to alert the monastery above and village below of happenings along the road.

"The zigzagged communication system along the valley was established in such a way as to communicate with each other all the way to the watchtower in the village of Livera, and to inform the monastery and Trabzon of the extraordinary developments in the valley," Köse said.

Köse compared the Observation Chapel to the small churches built on the slopes of Cappadocia's hills in central Turkey.

The interior of the chapel has different murals depicting the "heaven and hell, and death and life."

Visitors to the site can now access the chapel by climbing up a corridor and wooden ladders to reach it, according to Maçka district Mayor Koray Koçhan.

He noted that the murals in the chapel are authentic and are in very good condition, despite several illegal raids by treasure hunters.

Welcoming over 600,000 visitors annually, Sümela is located in Trabzon's Maçka district, within the Pontic Mountains range, at an altitude of 1,200 meters (3,900ft).