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
1999 earthquakes
1999 İzmit earthquake
Walls of Constantinople