On 1-5, 6 miles South of San Diego. Wedged between metropolitan San Diego and Imperial Beach at the southern end of San Diego Bay, Chula Vista is perhaps an unlikely place to find one of the last salt marshes remaining on the Pacific Coast. Salt marshes may be short on visual appeal, but they have profound ecological importance, not least in providing a habitat for some 200 species of bird. Salt marsh novices will find a trip around the Nature Interpretive Center (www.thelivingcoast.org), 1000 Gunpowder Point Drive, a fruitful undertaking.