Chiang Rai was the first capital of Lanna, the kingdom that covered the mountainous upper north of Thailand. Situated on the Mae Kok river, the town today is the capital of Chiang Rai Province and a paradise for temple-hoppers. Within the town itself are around 10 interesting temples, all of which are within walking distance of the town center - the unusual clock tower.
The temples to see are Wat Phra Kaew (or Phra Kaeo), Wat Phra Singh, Wat Klang Wiang, Wat Ming Muang, Wat Jet Yot, Wat Ngam Muang, Wat Phra That Doi Chom Thong, Wat Sri Gird, Wat Phra Non, and Wat Sri Bunruang.
Outside the town are the famous Wat Rong Khun (White Temple), Wat Prathat Doi Khao Kwai, and Wat Phra That Chom Si Thep. Further north in the province are Wat Phra That Doi Tung (near Mae Sai) and Wat Phra That Pu Khao (near Chiang Saen).
See the map in the Chiang Rai Guide.