Chiang Saen, located in Chiang Rai Province of northern Thailand, is a historic town with a rich heritage dating back to the ancient Kingdom of Lanna. Here are the top attractions and things to do in Chiang Saen:

1. Chiang Saen Historical Park: Explore the ruins of Chiang Saen Historical Park, which includes ancient temples, chedis (stupas), and city walls dating back to the 13th century. Marvel at the intricate architectural details and learn about the history of the region.
2. Wat Phra That Chedi Luang: Visit the impressive chedi (stupa) of Wat Phra That Chedi Luang, one of the largest and oldest temples in Chiang Saen. Admire the golden spire and explore the temple grounds, which offer panoramic views of the Mekong River.
3. Wat Phra That Pha Ngao: Discover the hilltop temple of Wat Phra That Pha Ngao, which offers stunning views of the surrounding countryside and the Mekong River. Explore the temple complex and pay homage to the sacred relics enshrined here.
4. Mekong River Cruise: Take a scenic boat cruise along the Mekong River, where you can enjoy views of the lush riverbanks, traditional villages, and historic sites. Many cruises offer stops at places of interest along the river, including the Golden Triangle.
5. Golden Triangle: Visit the Golden Triangle area, where the borders of Thailand, Laos, and Myanmar meet. Learn about the region's opium trade history at the Opium Museum and enjoy panoramic views of the Mekong River and neighboring countries.
6. Chiang Saen National Museum: Learn about the history and culture of Chiang Saen at the Chiang Saen National Museum. Explore exhibits showcasing artifacts, sculptures, and archaeological finds from the ancient city and surrounding areas.
7. Ban Sop Ruak (Sop Ruak Village): Explore the riverside village of Ban Sop Ruak, where you can visit local markets, shops, and restaurants. Learn about traditional crafts and watch demonstrations of weaving and pottery-making.
8. Wat Phra That Chom Kitti: Ascend the hill to visit Wat Phra That Chom Kitti, a temple with panoramic views of the Mekong River and the surrounding countryside. Explore the temple grounds and pay homage to the Buddha relics enshrined here.
9. Chiang Saen Lake: Relax by the tranquil waters of Chiang Saen Lake, where you can enjoy picnics, boat rides, and scenic views of the surrounding mountains. Watch the sunset over the lake for a memorable experience.
10. Local Cuisine: Sample authentic Northern Thai cuisine at local restaurants and street food stalls in Chiang Saen. Try regional specialties such as khao soi (curry noodle soup), gaeng hang lay (pork curry), and sai ua (grilled sausage).