Commercial facilities include a wide range of businesses and services to the public—amusement parks, arenas, casinos, convention centers, entertainment venues, hotels, media, outdoor festivals, parks, real estate, shopping centers, and more. These sites often attract large numbers of people, and they are usually built to be resilient under the expectation that these facilities will be subject to crowds, heavy equipment and items, and harsh weather. 
But they have also increasingly attracted attacks, as shooters and extremists seek easier access to a large number of victims, media attention, and damage.