For the uninitiated: Those people dressed in white and huddled together on the grassy area over by the south bank of the Miami River are not health-care workers on a break. They are students and practitioners of Santería, the Afro-Cuban religion whose spiritual emissaries, or orishas, rule all facets of man and nature. Believers can call upon these deities for guidance and assistance. It's no surprise that Miami, with its large Cuban population, should have lots of Santería devotees, but what is it about Sewell Park that draws the faithful? Look no further than the Miami River and its orisha, Oshún. Here's what OrishaNet, a comprehensive Santería Website (www.seanet.com/~efunmoyiwa/ochanet.html), has to say: "Oshún rules over the sweet waters of the world, the brooks, streams, and rivers, embodying love, fertility. She also is the one we most often approach to aid us in money matters.... All who are to be initiated as priests, no matter what orisha rules their head, must go to the river and give account of what they are about to do." Down near water's edge, hidden among the large rocks that form the bank, you can often find offerings to Oshún: candy, fruits, candles, and other favored objects.