Elephants are quite common in Thailand, you can even see them roaming around in Bangkok. Traditionally, the elephant was employed as beasts of burden; hauling logs and clearing forests, but they were also extensively used as machines of war. But the elephants you see in Bangkok are being escorted around by their Mahout (or trainer). They are usually trying to make money off of tourists buy selling pieces of sugarcane (which the elephant loves) for the tourists to feed the elephant. I do believe this is illegal in Bangkok and you do not see it too often. However, you can see many walking down the popular beaches in the evening hoping to sell the sugar cane. You see them in shows too, as you can see in the attached short video clip, where the elephants are trained to do trick of various levels of difficulty. Finally, there are many tourist areas where you can take a ride through the jungle on an elephant, which I have also done. So I am sure you will enjoy seeing these huge beasts on your trip to Thailand.