Yet, one local mattress store in San Antonio thought it'd be a good idea to acknowledge the anniversary with a "Twin Tower Sale."
Twitter users were horrified by the insensitive message. "You can't be serious" and "delete your account" were frequent reactions. The store did not delete the offending tweet, but on Thursday the store owner finally issued an apology.
Please let this be a lesson to any company trying to profit off of America's greatest tragedy.