Today, in Sioux Falls, South Dakota, an attempt to demolish a 20-story building failed to topple the structure, instead causing it to sink into its own basement. (A QuickTime movie of the whole thing is here.) The building, the Zip Feed Mill Tower, is thought to be the tallest in all of South Dakota; a weblogger, Hoby Brenner, has already posted to Flickr a bunch of pictures of the now-tilting structure. It’s a bit frightening that a building that tall can tilt that much without just crumbling to the ground!