LOS ANGELES, CA - APRIL 21:  A homeless man who goes by the name "Pepper" walks through a tunnel at the place where he sleeps along the graffiti-covered walls that line the banks of the Los Angeles River on April 21, 2006 in Los Angeles, California. Yesterday, officials unveiled plans for a 40-acre park along the concrete waterfront, an early step in the "Los Angeles River Revitalization Master Plan" to restore most of the 32-mile concrete-lined waterway to its natural state creating what an official called an "emerald necklace" of parks and riparian habitat. Throughout most of the year, the river's small, unthreatening but massive flooding, which occurs during winter storms, prompted engineers of the 20th century to encase the river in concrete. Environmentalists have long wanted to restore parts of the river.   (Photo by David McNew/Getty Images)