Yellowstone’s hot spring waters ultimately flow for thousands of miles before entering the ocean. But waters enter two different oceans—the Gulf of Mexico and the Pacific Ocean.

Hunting, off-road vehicle use, bike use, and some commercial uses are being considered for the Florida Panther National Wildlife Refuge, a nearly 27,000-acre refuge near Big Cypress National Preserve in Florida that was established in 1989 to protect habitat for the endangered cat while allowing for "limited visitor use."

Tropical Storm Elsa was tracking towards Dry Tortugas National Park off the southern tip of Florida, but was not expected to greatly impact the park.

Rising 30 feet and more above the blue waters of Lake Powell, the gray, crusty band of mussel shells reflects an invasion that has swept through the ecosystem practically unimpeded.