It's sizzling hot in San Diego, but the ocean's largest predator is keeping people away from the city's most popular beach. A 2-mile stretch of Mission Beach was closed after a lifeguard on a rescue board spotted a great white shark a few dozen yards away, the Los Angeles Times reports. Hundreds of swimmers were ordered out of the water. This is the first time a shark sighting has closed the beach "for as long as anyone can remember," a rescue department spokesman says. The beach will remain closed until authorities searching the area with boats and helicopters decide it's safe to go back in the water.