Killdeer chicks raced noisily along the sand beach. A beaver glided on the glassy surface, then dove for cover with a slap of its tail. The only people watching at Lake Boutin in Trail of Tears State Park on this early spring evening was a father and son strolling the shoreline.

Missouri is known as the Cave State, but it also has its share of another geologic wonder – natural bridges and tunnels.<?xml:namespace prefix = o />

The massive formations are featured at four state parks – Bennett Spring, Grand Gulf, Ha Ha Tonka and, of course, Rock Bridge Memorial.