abandoned ruins of machu picchu incan citadel, the maze of terraces and walls rising out of the thick undergrowth, peru

machu picchu incan citadel abandoned ruins buildings walls plazas terraces ramps steep mountainous terrain andes mountains peru urubamba river sacred valley maze green undergrowth mystery blocks hike inca trail ringe cusco landscape engineering civilization ancient city stone peak huayna wayna pikchu mountain unesco world heritage site historic sanctuary peruvian seven wonders