It's the site of a victory in the war against terror, and I would use the standard iconography of military monuments: a solitary white pillar, good and tall, with an angel ("winged victory", if ACLU complains) on the top, standing on a very solid, preferably granite-cored, dado of light-colored stone with appropriate inscriptions on all four faces. Something like that could last for 2,000 years.
No metal to rust or corrode, no marble or concrete to crumble and erode, just solid, hard, incorruptible stonework.
It wouldn't post and wouldn't post, so I thought maybe I'd forgotten to hit "post" before refreshing.......