Within hours of the federal government shutdown, National Park rangers were trekking towards backpackers to warn them they had 48 hours to leave the confines of the park.
The closures are costing so much -- $76 million a day -- that some states are dipping into their own funds to re-open their "national treasures."
During the government shutdown of 1995-96, parks didn't take the same hit because the closures came during off-peak months. But October is prime tourist season for many parks. The National Park System recorded 279 million visits in 2011.
Still, it's not likely that many national park lovers agree with Republican Ted Cruz, who protested the closures at a World War II monument in Washington, D.C., that national parks should remain open during a government shutdown.
The Coalition of National Park Service Retirees, for example, "believes that Congress should pass a budget this year and every year so the federal government of the United States can always be open -- including all National Parks. Our position is that Congress needs to get its act together and stop playing partisan games by passing a federal budget now and in all future years," said Joan Anzelmo, spokesperson for the Coalition.