Our national parks were the first of their kind in the world, though thankfully, many other nations now emulate this protection for their unique and rare natural places. I've been to 47 of our 58 national parks so far and intent to visit 3 more in September.
The Sierra Club came up with this interesting "map" of our national parks, emulating a transit map as you might find in Chicago or New York.
Count how many of our wondrous parks you have experienced firsthand (click to enlarge)...
(NOTE: American Samoa and Virgin Islands National Parks are omitted from map.)