The subcategories of conventions are what give each its own distinct flavor. These details determine the general attitude and scope of a convention, but so do the attendees, and seemingly identical conventions in two different areas may have vastly different results. The grand master of conventions is the World Science Fiction Convention, first run in New York in 1939. The Worldcons are large enough to collect thousands of pros and fans from all over the planet, and usually do. Most, but not all, conventions have a variety of basic elements, but a lack of an element shouldn't be taken as a weakness.
Many conventions combine local and international guests to satisfy the needs of the audience.
Many conventions feature comics writers and artists, while others bring in television and film actors, screenwriters, directors, and producers, as well as publicists to promote upcoming projects. Most conventions set up panels and lectures for the guests to interact with the public, but others allow the guests to free-range with fans and chat in more informal settings. The Dealers' Room. Often the largest room in a convention, the dealers' room is one of the main bases of operation at a convention. Depending upon the con's subject matter, the dealers may include new and used booksellers, artists selling limited edition prints, comics retailers, costumers and jewelers, glassblowers, book and magazine publishers, collectible toy dealers, and just about anything else one can imagine.