Waqrapukara or Waqra Pukara (possibly from Quechua waqra horn, pukara fortress, “horn fortress”) is an archaeological site in Peru located in the Cusco Region …

It was declared a National Cultural Heritage Site by the Ministry of Culture in July 2017. The building is said to be an Inca sanctuary.

At 4,140 m (13,580 ft) you seriously need to be acclimatized to make the 10k trek roundtrip.

BBC posted a trip report.

Check Puyca Expeditions to see how you could be guided to the remote site.