Doi Inthanon is Thailand's highest mountain at 2,565 metres, in a national park declared in 1954 and home to some 500 bird species. Near the summit stand two royal chedis: Naphamethinidon, built in 1987 for King Bhumibol's 60th birthday, and Naphaphonphumisiri, built in 1992 for Queen Sirikit's, set in flower gardens above the hills. On the way are Wachirathan Falls and Karen villages. Near the top it can fall to about 6°C in January, so bring something warm.