The Flight 93 National Memorial in Shanksville, Pennsylvania, is a place of deep symbolism and architectural precision. One "fun" (or fascinating) fact is that the Tower of Voices, which stands 93 feet tall, contains 40 wind chimes—one for each of the passengers and crew members who perished. Each chime is tuned to a different tone to create a unique "discordant harmony" when the wind blows. Another fact is the Wall of Names, which consists of 40 polished marble panels that follow the exact flight path the plane took in its final moments. The memorial site itself was previously a reclaimed strip mine, and the design was chosen through an international competition that received over 1,100 entries. Additionally, a massive 17-ton sandstone boulder marks the actual point of impact in the "sacred ground" area, which is off-limits to the public. Visitors can also see the "Hemlock Grove," where many original trees still bear scars from the explosion. The memorial is designed so that the sun sets directly behind the Wall of Names on the anniversary of the crash every September 11th.