(CNN) -- In Yemen, there is a race against time to save the historic Old City of Sana'a from the forces of modernization.
The sprawling metropolis that is modern Sana'a is the bustling capital of Yemen. But it occupies a site that has been inhabited for more than 2,000 years, and it boasts a historic quarter as beautiful as any in the world.
The Old City is made up of some 8,000 buildings, including its distinctive multi-storey tower houses. Built of earth, they are adorned with painted white "filigree" motifs that look like icing sugar on fairytale gingerbread houses.
Most buildings are between 200 and 500 years old, but some are much older, such as the Great Mosque, said to have been constructed in the seventh century, while the Prophet Muhammad was still alive.
Declared a World Heritage Site in 1986, the Old City is now threatened by urban growth, modernization and the unavoidable realities of ageing.
Dr. Abdullah Zaid Ayssa is president of Yemen's General Organization for the Preservation of Historic Cities, and he is tasked with restoring Sana'a's fading beauty.
"The Old City is really unique, with unique architecture and buildings," he told CNN.
"It is an old city, but it is alive, and we are planning to keep it alive without harming its architectural fabric and value.
"You have growing families, you have to think about expansion and how you deal with that. It's very difficult -- it's a living city, it's not a monument."
It's that need to preserve the Old City without turning it into a museum piece that provides Ayssa with his most difficult challenge.
UNESCO reports that new homes and public buildings have been constructed in gardens and green spaces, increasing the building density in the area. Fountains and wells have been abandoned and demolished, and incongruous water tanks and satellite dishes have begun to appear on traditional homes.
It also noted a widespread "soukization" of residential quarters, with the introduction of new retail areas at street level
"The ground floor [of homes] used to be used as a stable or for animals but some people are opening the ground floor as a shopping area," said Ayssa. "And we are trying to control that and organize that."
Efforts to preserve the Old City include increasing awareness of its fragility among the estimated 80,000 people who live there. That includes encouraging locals to use traditional materials when making alterations to their homes.
Many houses have collapsed after their shallow foundations were weakened by water seepage from pipes installed in recent decades.
"People understand and are very proud of their heritage but we have to convince them that the protection of the city is important," said Ayssa.
"If they don't realize that concept they won't care about it when it comes to the reality and economics of daily life.
"It costs money to preserve the Old City. It is very expensive but the challenge is how to create an income from it. We need to create internal income for preservation of the city, not just rely on outside support."
One way preservation and economics can go hand in hand is by encouraging tourism to the region. But ongoing concerns over security mean Sana'a has yet to attract visitors in the numbers its beauty merits.
The Yemeni government is working to improve the country's reputation abroad, hiring foreign PR companies to help and recently launching a series of tourism projects to worth $1 billion to be rolled out over the next five years.
But if it can retain its historic splendor, the Old City could still be charming visitors for centuries to come.