Thought I'd post a few unusual, lesser known facts about the USA's national parks:
(1) The most pure, clear water in the world is in Crater Lake in the southern part of the state of Oregon. It is so blue that one person wrote to their Congressman protesting it being "dyed" blue--not realizing that it happened naturally. The reason for it being so clear is that there is no water flowing into it (because it is so high) or out of it and therefore all the water came from a trillion years of rainfall.
(2) Yellowstone National Park in Wyoming is actually located primarily within the center of the world's largest volcano (estimated at 48 miles in diameter). For this reason, seismic measurements are taken everyday, just in case it should decide to explode (and thus destroy most of the western US in the process).
(3) Glacier National Park (Montana) is the only national park in the US that can be reached directly by train. There is a regular amtrak stop right at the park.
(4) Volcano National Park in Hawaii has added new land (from lava flows) every day since 1983,
(5) Because it winds back and forth so much, the part of the Colorado River that runs throught the Grand Canyon (Arizona) is 2,770 river miles long.
(6) Mammoth Caves in Kentucky has a known length of over 360 miles long (and possibly is as much as 1,000 miles long). It's known length of 360 miles long is over 3 times as long as any other cave structure in the world
(7) The original Indian name for Death Valley (California) meant "Land on Fire".
(8) The location in the US considered the best place to see wildlife is Yellowstone in Wyoming; the location considered the best to see water wildlife is the Everglades in Florida.
(9) There are roads through the wilderness in Alaska that normally carve their way through 30 foot snow drifts in winter.