d an
enormous cross-section of the acropolis. This erosion cut away a large portion
of the eastern part of the acropolis and revealed a vertical cross-section that
measures 37 meters (121 ft) high at its tallest point and 300 meters (980 ft)
long. The Carnegie Institution redirected the river to save the archaeological
site, although several buildings recorded in the 19th century had already been
destroyed, plus an unknown amount of the acropolis that was eroded before it
could be recorded. In order to avoid further destruction of the acropolis, the
Carnegie Institution diverted the river southwards in the 1930s; the dry former
riverbed was finally filled in at the same time as consolidation of the cut in
1990s.
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. A tomb was looted in 1998 as it was being excavated by archaeologists
