The traditional top hat has been around since late Victorian times, when formal dressing was the only option for the gentleman. The top hat is a tall, flat-crowned design with a broad brim. Originally the all-purpose choice of the Victorian gentleman, the top hat was worn often in combination with a morning suit or a white tie even as late as the 1930s.
Today, the modern versions of these hats provide an elegant option for some weddings and other formal occasions. Usually it will be worn with equally formal attire such as tailcoats (the traditional “top hat and tails” combination) or Edwardian-style frock coats. This kind of outfit will often involve white gloves too, though these are normally carried and rarely worn.
Top hats are also required for some royal events and even some sporting occasions, such as dressage. Magicians in the mid 20th century have also given this hat a new lease of life, as a standard prop for magic tricks.
If you wear a top a hat, it normally belongs on your head – unless you are greeting ladies, in which case you should hold it (and your gloves if you have them) in your left hand. When entering a building, of course, no hat should be worn; it is usual to leave top hats and gloves at the door – typically with a doorman or usher, or on a hall table.