In which state is the Palo Duro Canyon located?

What is the term for the Arctic region north of the tree line? Which of the following research stations is located on the Antarctic Peninsula? What is the name of the largest fjord in the Arctic? What is the name of the famous canyon in Arizona, USA? In which country is the Taroko Gorge canyon located? What is the name of the famous canyon in Utah, USA, known for its steep red rock walls? In which state is the Black Canyon of the Gunnison located? What is the name of the famous canyon in Arizona, USA, known for its blue-green waters?