Strange as it sounds, Yang Guoxing, a farmer in Northwest China, has lived inside the Great Wall all his life.

Yang's father grew up in a tiny village in Tongxin county in the Ningxia Hui autonomous region. When he married in 1950, he carried his new wife over the threshold of a cave house - dug through a section of the Great Wall. Such houses can be found across hillsides in northwestern China.

Unexpectedly, the presence of the cave houses has meant better preservation of parts of the ancient wall, because sections of it are enclosed and protected by a family's courtyard and kept intact. Old bricks from the wall sections outside the courtyards were often taken to sell or to use as building material.

Great Wall Pass, where Yang's home is located, was built in 1577 during the Ming Dynasty (1368-1644).

When one enters the courtyard, the arch door of the cave house in the wall's gray stone comes into view. On one side is a fortified tower, with lush wild grass beneath.

Yang Guoxing was born in this house in 1974, the ninth of 10 children. He recalled that in the 1980s, many residents sold bricks they had taken from the Great Wall. One brick could be sold for 0.5 yuan ($0.07).

Although under pressure to raise his family, Yang's father, who was working at the township's grain depot, did not sell any bricks from their courtyard.

"He always told us that we should protect our home and never let others steal our bricks," Yang said.

Gradually, the younger Yang developed a passion to protect the Great Wall. He has searched for information in books and online to better understand the history of the area where his father made their home.

"Some tourists ask to visit our home, and I am happy to show them around and answer their questions," he said.

Most of the time, however, Yang works in the city.

In 2014, Yang and his siblings built a three-room brick house about 100 meters away. Though they have moved out, family members still look after their Great Wall house.

"I will always protect that part of the Great Wall and try my best to maintain its original appearance," Yang said, adding that this Great Wall section is in dire need of restoration.

Gu Yongcun, head of Tongxin county's cultural relics bureau, said the family dwelling under the Great Wall did, in fact, help to maintain the original site.

Living beneath the wall violates modern laws and regulations, but those were not in place when the house was built, Gu said.

Great Wall Pass was listed as a provincial-level protected site in 2010. However, the local government has not adopted any restoration measures because of a lack of funding. It would cost about 40,000 yuan to restore just 1 meter of the wall.

"But the good news is that the regional government will allocate some funds to help the restoration this year, and we are doing the budget," Gu said.