(CNN) -- Moammar Gadhafi's Bab al-Aziziya compound is the heart of his nearly 42-year rule, a symbol of his defiance of the West.
The sprawling complex houses modern government offices, the Bedouin tent in which Gadhafi received visitors and stands of palm trees. A bombed-out building remains as a monument to a 1986 U.S. airstrike that killed one of Gadhafi's daughters, along with a statue of a Libyan fist crushing an American jet.
And Tuesday evening, after rebel fighters who have battled Gadhafi's forces for six months punched into the compound, it was wreathed in smoke. Rebels posed around the statue and fired hundreds if not thousands of rounds of ammunition into the air in celebration, spurring the occasional rebuke from senior fighters.
The rebels picked through the compound in search of Libya's longtime strongman, but one fighter told CNN that neither Gadhafi nor any members of his family had been found. Bab al-Aziziya appeared to have been abandoned so quickly that a teakettle remained heating on a stove in one building, he said.
"They ran away, all of them," he said. "They have gone underground."
Bab al-Aziziya, located near Tripoli's Mediterranean shore, is believed to be undergirded by a network of tunnels.
Abubaker Saad, a former Gadhafi aide, told CNN that at least one of the older buildings on the site was built atop a bunker four stories underground. But he said it was unlikely that Gadhafi had been in the complex before it was overrun Tuesday, since it had been targeted by repeated NATO airstrikes during the last few months of fighting.
"You have to remember that he is a military man," Saad said. "He knows they have weapons that could penetrate those bunkers." In addition, he said, the poor quality of the audio messages Gadhafi delivered on state television Sunday suggests Gadhafi "is speaking from a distance."
CNN National Security Contributor Frances Townsend had what she called an "absolutely bizarre experience" meeting there with the eccentric Libyan leader in the summer of 2007, when she served as President George W. Bush's chief counterterrorism advisor. Townsend said she was required to ride to the compound in a car sent by Gadhafi, and the Libyans tried to separate her from her U.S. security detail, but one agent was able to jump into the car before it departed.
Once through a series of checkpoints, Townsend said, the driver stopped in front of the bombed-out museum -- an echo of a U.S. raid in retaliation for the bombing of a Berlin disco that killed two American servicemen. She then waited in one of the many spacious rooms decorated in traditional Arab fashion, with couches lining the perimeter, for her audience with Gadhafi.
The Libyan ruler's tent was surrounded by a field of knee-high grass, as well as both uniformed and plainclothes guards. Inside, it was filled with numerous rugs and couches.
Other visitors say the compound includes a mosque, a library and the residences of other government officials.
CNN's Sara Sidner, Thomas Evans and Pam Benson contributed to this report.