From the History Commons Groups blog:
A large number of entries have been added to the Complete 9/11 Timeline at History Commons. Most of these focus on the events of September 11, 2001, including the actions of White House personnel in response to the terrorist attacks that day, and a number of apparent threats to President Bush and his plane, Air Force One.
White House Officials Visited Emergency Bunker during Exercise
A new timeline entry describes a training exercise held shortly before 9/11 in which some senior White House staffers were shown to the Presidential Emergency Operations Center (PEOC), a bunker below the White House where numerous government officials went on September 11. Following the first attack on September 11, Josh Bolten, the deputy White House chief of staff, was called by a former member of the Clinton administration who wanted to check that he was aware of the PEOC.
Bolten, according to his own recollection, alerted National Security Adviser Condoleezza Rice to the second crash at the World Trade Center after seeing coverage of it on television. Later on, he headed to the PEOC where he joined Vice President Dick Cheney and other government officials.
Also early on the morning of September 11, a sheriff in Sarasota, Florida, was surprised to find that when he contacted colleagues who were with President Bush’s Secret Service detail, shortly after he saw the TV reports of the first crash at the WTC, those colleagues were unaware of what had happened in New York.