 Structures 10L–19, 20, 20A and 21 were all destroyed by the Copán River as it eroded the site away, but had been recorded by investigators in the 19th century.Copán was declared a UNESCO World Heritage Site in 1980, and UNESCO approved funding of US$95,825 between 1982 and 1999 for various works at the site.Looting remains a serious threat to Copán.