Kandy is Sri Lanka's second city and its spiritual heart — a compact, hilly place set around an artificial lake, with the famous Temple of the Tooth Relic sitting right at the water's edge. It was the last capital of the Sinhalese kings before the British arrived in 1815, and that royal history gives it a weight that Colombo, for all its size, lacks. The surrounding hill country is strikingly beautiful: green, cool, and layered with tea plantations.
The Temple of the Tooth (Sri Dalada Maligawa) is the city's defining sight and one of the most sacred Buddhist temples in the world. The tooth — a relic of the Buddha — is housed here under heavy guard and brought out for veneration during puja ceremonies three times daily. If you're staying nearby, expect to be woken at midnight, 4am, and 7am by devotional drumming and chanting through loudspeakers — authentic, unavoidable, and strangely moving once you adjust to it.
Kandy makes an excellent base for the surrounding region. Two or three days in the city is enough for most visitors: walk around the lake, visit the temple, wander the market streets behind the bus stand, and take in the Kandyan dance performance held most evenings. From here you can reach Pinnawela and the Elephant Orphanage, the cave temples at Dambulla, and Sigiriya's rock fortress — all within a few hours. The scenic train journey east through the hills toward Ella is one of the finest rail rides in Asia and well worth doing slowly.