kids are selling fireworks across from the marcus aurelius arch. one is constantly reminded that libya was once a vital part of the ancient roman empire. that was nearly 2,000 years ago. tonight, i was told, was going to be an even bigger, wilder celebration in martyrs square, but something has happened since last night. the british foreign office has just told all uk citizens to leave benghazi, libya's second largest city, due to an unspecified threat. the libyan government, such as it is, has denied any basis for such drastic action. a lone cherry bomb now and again, an awkward flurry of roman candles. the buzz of last night's chaotic