The 2012 World Monuments Fund Watch List

Nasca Lines and Geoglyphs, Peru
These strange, massive pictograms in the Peruvian earth inspired a generation of quack theorists to posit a time when aliens from other galaxies left their secrets and imprints on our planet. The Nasca lines and glyphs — potentially 2,500 years old — rank among the most beguiling legacies of Mesoamerica, but they are at risk of damage now from an influx of tourists.

• The 2010 WMF Watch List