The land walls run through the heart of modern Istanbul, with a belt of parkland flanking their course. They are pierced at intervals by modern roads leading westwards out of the city. Many sections were restored during the 1980s, with financial support from UNESCO, but the restoration program has been criticized for destroying historical evidence, focusing on superficial restoration, the use of inappropriate materials and poor quality of work. This became apparent in the 1999 earthquakes, when the restored sections collapsed while the original structure underneath remained intact. The threat posed by urban pollution, and the lack of a comprehensive restoration effort, prompted the World Monuments Fund to include them on its 2008 Watch List of the 100 Most Endangered Sites in the world.