Many if not most countries of the world, of course, set aside choice pieces of territory to protect and often showcase precious natural environments. But thanks to its size and a conservationist ethos dating back to the mid-19th century (though these days being increasingly threatened), few countries offer the number and diversity of natural parks – state and national – as the United States of America, from “sea to shining sea”, as its national anthem poetically puts it. And its 400 national p
