BDSM stands for "Bondage & Discipline, Dominance & Submission, Sadism & Masochism"
It's like a trip to unique new world.
You can see a person being handcuffed using a rope, someone being whipped, another person trying out the new electro shocking device ... In the shops of the exhibitors you can find heavy iron shackles, ropes for shibari (the traditional Japanese way of tying a bottom), fashion made out of latex, "furniture" for the playroom like a Saint Andrew's Cross, gas-masks and straitjackets.
When you walk between the exhibitors, you will encounter a lady with a handcuffed slave on the leash, a person being dressed like a pony pulling a carriage or a gay couple wearing nothing else than a locked chastity belt.
It's a parallel universe with a great spirit and lot of smiling and happy people.