The Tourist Authority of Thailand (1600 New Phetchaburi Rd., Sukhumvit. 02/250-5500. www.tourismthailand.org. Subway: Sukhumvit; Skytrain: Asok), open daily 8:30 to 4:30, has more colorful brochures than hard information, but it can supply material on national parks and out-of-the-way destinations. A 24-hour hotline provides information on destinations, festivals, and the arts. You can use the hotline to register complaints or request assistance from the Tourist Police.