(CNN) — A fire erupted Friday in two buildings that are part of a Shanksville, Pennsylvania, memorial to United Airlines Flight 93, which crashed on September 11, 2001, officials said.
Seven fire companies responded to the blaze, which started about 3 p.m., said Geraldine Budzina, a Somerset County dispatcher. No injuries were reported.
Firefighters were trying to prevent the fire from spreading, Budzina said. The cause was unknown.
The memorial park is dedicated to the 40 passengers and crew who died when Flight 93 crashed outside the town of Shanksville in southwestern Pennsylvania
The plane went down, killing all on board, as passengers fought back against the hijackers, according to post-9/11 investigations.
The memorial, still incomplete, includes a visitor’s center with traditional and interactive exhibits, public programs, and information about the history of Flight 93.
On 9/11, United Airlines Flight 93 was traveling from Newark, New Jersey, to San Francisco when hijackers took over the plane, according to the 9/11 Commission.
Investigators said the terrorists were most likely trying to turn the airplane toward Washington to hit a major political target.
Here’s a look at what you need to know about the Flight 93 National Memorial. It is a memorial to the 40 passengers and crew who died on United Flight 93 on September 11, 2001 near Shanksville, Pennsylvania.
Facts: When complete, the memorial will encompass 2,200 acres. It is managed by the National Park Service. Phase II of construction is planned to be completed in 2015.
The memorial has received an average of 300,000 visitors a year since it’s dedication in 2011.
Upon completion, features of the memorial will include the “Tower of Voices,” a 93-foot-tall tower with 40 wind chimes, 40 memorial groves, a memorial plaza and a field of honor.
Timeline: September 11, 2001 - United Airlines Flight 93, originally traveling from Newark, New Jersey, to San Francisco, crashes in a field near Shanksville, Pennsylvania. Hijackers direct the plane towards a new, unknown location or target, when it is disrupted by passengers. All 40 passengers and crew and four hijackers are killed.
September 24, 2002 - The Flight 93 National Memorial Act is passed, creating the country's 386th national park.
September 7, 2005 - A design by Paul Murdoch Architects of Los Angeles, "The Crescent of Embrace," is chosen for the memorial. A committee of 15 people, including family members of victims, chooses it out of more than 1,000 entries.
August 31, 2009 - Interior Secretary Ken Salazar announces the National Park Service has reached agreements with seven of eight landowners to purchase the land necessary for the memorial, at an estimated $9.5 million. The eighth parcel, owned by Svonavec, Inc., will be taken by eminent domain after an agreement cannot be reached. This parcel includes most of the crash site.
November 7, 2009 - The groundbreaking ceremony at the memorial site takes place.
August 4, 2011 - The National Park Foundation announces it will match up to $2 million in donations.
September 10, 2011 - Flight 93 National Memorial is dedicated. Vice President Joe Biden attends the ceremony.
September 11, 2011 - President Barack Obama participates in commemorations at the memorial site.
May 30, 2012 - The National Park Service completes the planting of the 40 Memorial Groves.
April 2013 - More than 500 volunteers plant 15,500 seedlings across 23 acres. Trees planted for reforestation in the area will serve as a windbreak for the trees in the Memorial Groves.