A maintenance project has finished on the Jiayu Pass, a famed part of the Great Wall built in the Ming Dynasty (1368-1644) in Jiayuguan city, Northwest China's Gansu province.

The Jiayu Pass is regarded as the western start of Ming Dynasty Great Wall and continues to the Shanhai Pass in Hebei province on China's eastern coast.

Inscribed on the UNESCO list in 1987, the pass features 11.7-meter-high tower walls and meanders across undulating hills and rocks. The site attracted 1.1 million visitors in 2016.

Qiu Jian, a relic protection official, said the work used traditional construction methods and materials, helping to restore the past glory of the military fortress and protect its cultural heritage.

The Great Wall had a poor drainage system, and was cracked and weathered by dry and windy conditions before maintenance began in 2012.

The government-funded work cost over 300 million yuan ($45 million), and renovated a 3.5 square km area of the Great Wall and a 70 square km scenic zone.

The renovation started in May, 2012 and took five years including gate and beacon towers that Jiayuguan section of the Great Wall, the Jiayuguan world cultural heritage monitoring center and Jiayuguan world heritage exhibition.

Natural factors like wind erosion, weathering, earthquakes and floods, as well as human factors like construction and other activities had caused much damage over time.

Part of the Jiayuguan section's walls were cracked, with rain and wind having corroded their foundations, leading to the weakening of beams and roof leakage, said Qiu Jian, head of Gansu Provincial Cultural Relics and Archaeology Institute.