I belong to a geology club and we had a very intersting speaker talk about the geology of the World Trade Center.
Charles Merguerian is in the geology department at Hofstra. He studied the excavation and did a presentation called “The Geology of Glacial Underground Waterfalls Discovered in the Excavation for the New World Trade Center.” They found rounded impressions smoothed by boulders under the waterfalls. Here is an article about the geology of the site: " At Ground Zero, Scenes From the Ice Age"
@Trigger Hippie I read somewhere that the salts in this area turned magnificent colors of greens and blues after the detonation. I can't find any color photos of this and how in the world was someone able to stand down there without getting radiation poison.