located some 110 miles off the coast of texas and louisiana, flower garden banks may be the oddest of the sanctuaries - three salt domes hump up from the floor of the gulf of mexico, toupeed by the northernmost coral reef in the continental united states. the banks are a diver's paradise, and the seven- to eight-hour trip to the area (most outfitters leave from freeport, texas) is worth every minute. from january through april, scalloped hammerheads visit, and in august or september (depending on the date of the full moon), the area erupts in a lovely undersea snowstorm, the result of a mass coral spawn. outfitters - who know the approximate timing - offer spawning cruises.


gray's reef national marine sanctuary, graysreef.noaa.gov, (912) 598-2345
roughly 20 miles off sapelo island, georgia, this 17-mile piece of open ocean is home to a sandstone reef fat with corals, sponges, and fish, making it one of the most popular diving and sportfishing (grouper, black sea bass, snapper, mackerel) spots off the georgia coast. don't dive or fish? visit the interpretive centers at the university of georgia's marine education center and aquarium on skidaway island (www.uga.edu/aquarium, 912-598-2496) or the tybee island marine science center (www.tybeemsc.org, 912-786-5917).


gulf of the farallones national marine sanctuary, farallones.noaa.gov, (415) 561-6622
located northwest of san francisco, this sanctuary abuts some of america's loveliest shore, offering beaches, wetlands, and great tide pooling (try duxbury reef tide pool for starters). the sanctuary is a breeding ground for harbor seals, elephant seals, pacific white-sided dolphins, and more than 300,000 seabirds. whale-watching trips and nature expeditions head for the farallon islands, where they might spot gray, humpback, and blue whales, and, though outfitters won't guarantee it, possibly great white sharks near the islands, especially from september through november. more timid souls can visit the sanctuary visitor center at crissy field (near the golden gate bridge, 415-561-6625).