Libyan rebels took control of most of Tripoli in a lightning advance Sunday, August 21, celebrating the victory in Green Square, the symbolic heart of Moammar Gadhafi's regime. Gadhafi's defenders quickly melted away as his 42-year rule crumbled, but the leader's whereabouts were unknown and pockets of resistance remained.

State TV broadcast Gadhafi's bitter pleas for Libyans to defend his regime. Opposition fighters captured his son and one-time heir apparent, Seif al-Islam, who along with his father faces charges of crimes against humanity at the International Criminal Court in the Netherlands. Another son was under house arrest.

By the early hours of Monday, opposition fighters controlled most of the capital. The seizure of Green Square held profound symbolic value- the plaza was the scene of pro-Gadhafi rallies organized by the regime almost every night, and Gadhafi delivered speeches to his loyalists from the historic Red Fort that overlooks the square. Rebels and Tripoli residents set up checkpoints around the city, though pockets of pro-Gadhafi fighters remained, the Associated Press reported.

Gadhafi is the Arab world's longest-ruling, most erratic, most grimly fascinating leader - presiding for 42 years over this North African desert nation with vast oil reserves and just 6 million people.