Here's a list of 6 such attractions that find a place in the top-tier:
Ko Phi Phi: Ko Phi Phi Island is an idyllic location that features warm waters and soft white sand. It is actually a small archipelago in the Krabi province in Southern Thailand and is extremely popular for its beauty and charm. In other words, it's the ultimate island paradise with a relaxed vibe that appeals to almost every individual.
The Grand Palace and Wat Phra Keaw: One of the must-see sights in the capital city; your Bangkok holidays are incomplete if you do not visit this attraction. The Grand Palace, built in 1782, is a famous landmark and dazzles with it's grandeur and architecture. Home of the Thai king, the royal court and the administrative seat of government, it will render you speechless with its intricate details. The Palace also houses the highly popular and revered Wat Phra Keaw or the Temple of the Emerald Buddha.
Bangkok's Floating Markets: If you've ever read through a brochure for Thailand's package holidays, you've certainly come across Bangkok's floating markets. These vibrant floating markets, with their floating boats piled high with fresh fruits and vegetables, ready-to-drink coconut juice and local food cooked from floating kitchens are a bigger cultural hub than any other location in Thailand.
Ayutthaya: Ayutthaya is the former capital of the Kingdom of Siam and is one of Thailand's leading historical sites. It has an incredible collection of ruins in the city centre. The city surrendered its status a few centuries ago but the ruins that remain give a good idea of the kingdom's former power.
Similan Islands: The Similan Islands located in the Western Andaman Sea are rated as one of the best dive destinations in Thailand. The archipelago is made up of nine islands that are covered in a tropical jungle with white sandy beaches, and the best part might just be the east and west facing dive sites and the flourishing coral reefs.
Chiang Mai: The night market of Chiang Mai usually spreads along several blocks and along the footpaths as well as the buildings and temple grounds and contains handicrafts, arts clothing and imported products. Like the floating markets, they're also full of cultural enrichment and are a must-visit.
Thailand is known for the warmth of its people, its soul-satisfying food and awe-inspiring natural beauty. It's about time you began planning your trip to this wonderful little gem in the Far East.