US

National Park Service showing off Flight 93 visitor center construction on eve of anniversary

  • Sarah Kowalczyk, 6, from Lake Village, Indiana, holds a giant flag while participating in a sunset memorial service at the Flight 93 National Memorial on Wednesday, September 10, 2014. (AP Photo/Gene J. Puskar)

    Sarah Kowalczyk, 6, from Lake Village, Indiana, holds a giant flag while participating in a sunset memorial service at the Flight 93 National Memorial on Wednesday, September 10, 2014. (AP Photo/Gene J. Puskar)  (The Associated Press)

  • In this photo taken with a fisheye lens Jeff Reinbold of the National Park Service, left, walks with Gordon Felt, who lost his brother Edward Felt on Flight 93, during a tour of the Flight 93 Visitors Center Complex that is under construction overlooking the crash site of Flight 93 at the Flight 93 National Memorial on Wednesday, Sept. 10, 2014 in Shanksville, Pa. Construction is scheduled to be completed by late 2015. (AP Photo/Gene J. Puskar)

    In this photo taken with a fisheye lens Jeff Reinbold of the National Park Service, left, walks with Gordon Felt, who lost his brother Edward Felt on Flight 93, during a tour of the Flight 93 Visitors Center Complex that is under construction overlooking the crash site of Flight 93 at the Flight 93 National Memorial on Wednesday, Sept. 10, 2014 in Shanksville, Pa. Construction is scheduled to be completed by late 2015. (AP Photo/Gene J. Puskar)  (The Associated Press)

  • ADDS LOCATION - Visitors to the Flight 93 National Memorial hold a giant flag as they participate in a sunset memorial service at sunset on Wednesday, Sept. 10, 2014, in Shanksville, Pa. (AP Photo/Gene J. Puskar)

    ADDS LOCATION - Visitors to the Flight 93 National Memorial hold a giant flag as they participate in a sunset memorial service at sunset on Wednesday, Sept. 10, 2014, in Shanksville, Pa. (AP Photo/Gene J. Puskar)  (The Associated Press)

The National Park Service will provide a tour of the visitor center being built at the Flight 93 National Memorial on the eve of the 13th anniversary of the Sept. 11 terrorist attacks.

The memorial marks the spot where United Airlines Flight 93 crashed in a field about 75 miles southeast of Pittsburgh after passengers fought back against hijackers.

A permanent memorial was dedicated on the 10th anniversary of the attacks. Last year, the Park Service awarded a $20 million contract to URS Group Inc. of Morrisville, North Carolina, to build the visitor center and do other site improvements.

The visitor's center is expected to open late next year. Officials hope it will increase the number of people who visit the memorial annually from about 300,000 to 500,000.