sentences:  Teoberto Maler first reported Yaxha's existence after visiting the ruins in 1904.The Carnegie Institution of Washington mapped the ruins in the 1930s and the site was again mapped in the early 1970s, at which time test excavations were undertaken.The Proyecto Nacional Tikal ("National Tikal Project") carried out a survey of architectural damage at Yaxha in 1987 and in 1988 the first work was undertaken in order to stabilise some of the structures.