On the north side of the Carquinez Straits, through which the Sacramento and San Joaquin Rivers flow into San Francisco Bay, Vallejo is a blue-collar maritime town that made national news by declaring bankruptcy in 2008, in the wake of the subprime housing crash. Longtime home of the huge and historic Mare Island naval shipyard, which from 1854 to 1994 built and maintained many of the country’s fighting ships and submarines, Vallejo also served as California’s state capital on two different occasions in the gold rush years of the early 1850s. These days, Vallejo’s one bona fide attraction is the theme park Six Flags Discovery Kingdom (707/644-4000, hours vary, daily summer, around $68), on the north side of town just west of I-80. Along with one of California’s most intense arrays of high-speed thrill rides (like 65-mph Medusa, or the even-faster Vertical Velocity), Six Flags is surrounded by more than 135 acres of kid-friendly animal attractions, so you can admire tigers, elephants, and dolphins, or feed the tropical birds and butterflies.