What is the name of the UNESCO World Heritage site located in the Namib Desert, known for its unique sand dunes?

Which UNESCO World Heritage site is located in the Peruvian Andes and features the Inca city of Machu Picchu? What is the name of the UNESCO World Heritage site located in the Democratic Republic of Congo, home to the lowland gor… What is the name of the UNESCO World Heritage site located in the Canadian Rockies, featuring glaciers and mountain pea… Which UNESCO World Heritage site is located in the Russian Far East and features a unique volcanic landscape? What river flows through China, Laos, Thailand, Cambodia, and Vietnam? What river flows through Russia, Kazakhstan, and China? What river flows through Germany, Austria, Slovakia, and Hungary? Which river forms part of the border between France and Spain?