Tens of thousands of Libyans celebrate in Benghazi on Sunday. (Gianluigi Guercia/Getty-AFP) Rebels take control of most of Tripoli

Libyan rebels raced into Tripoli in a lightning advance that met little resistance as Moammar Gadhafi's defenders melted away. The leader's whereabouts were unknown and pockets of resistance remained.

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  Obama says Gadhafi regime collapsing

Chicago-based parent United Continental Holdings said Sunday that it plans to spend $550 million on improvements, some of which customers will see as early as next month.