Aug. 24, 2011 -- The strongest earthquake to hit the East Coast of the U.S. in seven decades damaged landmark buildings in the Washington, D.C. area, while rattling the nerves of tens of millions, just three weeks ahead of the 10th anniversary of the September 11 attacks.
Though there are no known deaths after the quake that struck at 1:58 p.m. Tuesday, damage overall was estimated at $100 million.
The National Park Service discovered cracking in the stones at the top of the Washington Monument, which will be closed indefinitely, according to the Associated Press. While inspecting it via helicopter the NPS noticed a crack in what they refer to as the paramedian – at the very top of the triangle.
At the historic National Cathedral in Washington, D.C. damage has been confirmed to three of four pinnacles atop the tower, while reports indicated cracks appeared in the flying buttresses around the east end of the cathedral.
SEE PHOTOS: Earthquake Rocks East Coast Cities
Experts are working to assess the building damage, both structurally and aesthetically, according to a statement on the monument's official website.
Elsewhere in the capital, the largest metropolitan area close to the quake's epicenter, the Cross family from Michigan was at the top of the Washington Monument when the quake struck. They said that they felt the 555 foot monument sway nearly a foot, and said they felt pieces of the monument falling on them.
The White House and Capitol building were evacuated following the quake, and the Park Service closed all monuments and memorials on the National Mall. The Capitol was reopened by late afternoon for people to retrieve their things, according to the Associated Press.
In Louisa County, Va. -- the epicenter of the earthquake -- 911 dispatchers reported a massive spike in calls with some terrified residents phoning in to verify what had happened and seek consolation.
Virginia Gov. Bob McDonnell says preliminary reports show no significant destruction from Tuesday's earthquake - with one exception.
"Right near the epicenter in Louisa it appears that both the middle school and the high school did suffer damage and may have a problem operating here," McDonnell said.
Schools in seven counties in Virginia will be closed on Wednesday as damage is assessed across the area; several schools in Washington, D.C. and in Maryland will also be closed.
In New York the quake startled thousands of office workers who are anticipating the 10th anniversary of the September 11th attacks on the World Trade Center. Blocks from Ground Zero workers filed out onto the streets after the quake hit.
"I thought we'd been hit by an airplane," Marty Wiesner, who works at the federal courthouse in lower Manhattan, told the Associated Press.
In New York, District Attorney Cy Vance was holding a press conference to announce that charges would be dropped in the sexual assault case against French economist Dominique Strauss-Kahn, when his speech was interrupted by the quake. A look of shock crossed his face as all of his colleagues quickly raced to leave the platform.
Nuclear expert and physicist Dr. Michio Kaku told ABC News that the reason the East Coast earthquake was felt so far and wide is that there is a huge difference between the east and west coast topography. On the West Coast, tectonic plates are fragmented, so the energy is local and more concentrated – which is not the case on the east coast.
"We have the North American plate and so it rocks as one unit. Energy is scattered all the way to Canada for example," he said.
Kaku also warned that he feels that the East Coast dodged a bullet with Tuesday's earthquake, and should see it as a wake-up call.
"We have to prepare our building codes for the once in a century earthquake, we are not prepared at all," he said. "Our buildings don't sway like those in California and Japan. Our buildings would collapse if we had a major earthquake in Manhattan."
One person that did not feel any vibrations at all was President Obama, who is currently vacationing with his family in Martha's Vineyard, Mass. White House Deputy Press Secretary Josh Earnest today confirmed that Obama felt nothing as the quake rattled half the country.