Cusco city in 1535. Remains of the palace of the Incas, Qurikancha (the Temple of the Sun) and the Temple of the Virgins of the Sun still stand. Inca buildings and foundations in some cases proved to be stronger than the foundations built in present-day Peru. Among the most noteworthy Spanish colonial buildings of the city is the Cathedral of Santo Domingo, Cusco. The major nearby Inca sites are Pachacuti's presumed winter home, Machu Picchu, which can be reached on foot by the Inca Trail to Machu Picchu or by train; and the "fortress" at Ollantaytambo. Less-visited ruins include: Incahuasi, the
Machu Picchu zone exists above the area. UNESCO is considering putting Machu Picchu on its List of World Heritage in Danger. During the 1980s a large rock from Machu Picchu's central plaza was moved to a different location to create a helicopter landing zone. In the 1990s, the government prohibited helicopter landings. In 2006, a Cusco-based company, Helicusco, sought approval for tourist flights over Machu Picchu. The resulting license was soon rescinded. Authorities have struggled to maintain tourist safety. Tourist deaths have been linked to altitude sickness, floods and hiking accidents. UNESCO received criticism for allowing tourists at the location given high