Darren Williams spent four weeks this summer making a short but startling video that raises novel questions about the 2001 attack. The video, 9/11: Pentagon Strike," suggests that it was not American Airlines Flight 77 that slammed into the Pentagon, but a missile or a small plane. The video offers flashes of photographs taken shortly after impact, interspersed with witness accounts. The pictures seem incompatible with damage caused by a jumbo jet. Firefighters stand outside a perfectly round hole in a Pentagon wall where the Boeing 757 punched through; it is less than 20 feet in diameter. Propelled by word of mouth, Internet search engines and e-mail, the video has been downloaded by millions of people around the world. Williams created a Web site for the video, www.pentagonstrike.co.uk. Then he e-mailed a copy to Laura Knight-Jadczyk [who] posted a link to the video on the group's Web site, www.Cassiopaea.org. Within 36 hours, Williams's site collapsed under the crush of tens of thousands of visitors. But there were others to fill the void. In Texas, a former casino worker who downloaded the video began drawing almost 700,000 visitors a day. In Louisiana, a young Navy specialist put the video on his personal Web page. Suddenly, the site was inundated by more than 20,000 hits. "Pentagon Strike" is just the latest and flashiest example of a growing number of Web sites, books and videos contending that something other than a commercial airliner hit the Pentagon. Knight-Jadczyk said she never imagined anyone outside her group would ever view "Pentagon Strike." "The fact everybody's been sending it to his brother and his cousin ... reflects the fact that there is a deep unease," she said.