Ayutthaya was the capital of the Kingdom of Siam from 1351 until it was destroyed by a Burmese army in 1767. At its height it was one of the largest cities in the world, trading with China, Japan, Persia and Europe. The ruins of its temples, palaces and monasteries stand on an island formed by three rivers. The historical park has been a UNESCO World Heritage Site since 1991.

Wat Mahathat in Ayutthaya was built in the 14th century and was one of the most important temples of the kingdom, seat of the supreme patriarch. It was burnt in 1767. Rows of headless Buddha images and broken chedis remain among the brick walls. The best known sight is a stone Buddha head caught in the roots of a fig tree.

Wat Phra Si Sanphet was the royal temple inside the palace of Ayutthaya, used only by the king for ceremonies. It was built in the 15th century. Three large bell-shaped chedis in a row hold the ashes of three kings. A 16-metre standing Buddha covered with gold once stood here but was melted down by the Burmese in 1767. The three chedis are the symbol of the city.

Wat Ratchaburana in Ayutthaya was founded in 1424 by King Borommarachathirat II on the spot where his two older brothers died fighting for the throne. Its central prang is one of the best preserved in the city. In 1957 looters broke into its crypt, which held a treasure of gold objects and Buddha images. Some of these are now in the nearby Chao Sam Phraya Museum.

Wat Lokayasutharam is known for its huge Reclining Buddha, which lies in the open air among the ruins of Ayutthaya. The brick and plaster statue is about 37 metres long and 8 metres high. Its head rests on a lotus flower. The building that once covered it was lost long ago, and the figure is often draped in a bright orange robe by worshippers.

Wat Chaiwatthanaram stands on the west bank of the Chao Phraya River in Ayutthaya. King Prasat Thong built it in 1630, in honour of his mother. Its design, with a tall central prang surrounded by smaller towers, is based on the Khmer temples of Angkor. A gallery with 120 Buddha images once enclosed it. The temple is especially fine at sunset.

Phra Prang Sam Yot is a Khmer temple in the centre of Lopburi, built in the 13th century. Its three laterite towers, joined by corridors, were probably dedicated to Hindu gods and later used as a Buddhist shrine. The temple is famous for its many macaque monkeys, which live in and around the ruins. Each November a monkey festival is held with a buffet of fruit for them.

Kamphaeng Phet Historical Park protects the ruins of a fortified city founded in the 14th century as a frontier post of the Sukhothai kingdom. Its name means diamond wall. Many temples lie in a forest area outside the walls, where monks once lived in quiet. Laterite Buddha images, elephant bases and chedis stand among the trees. It is part of the Sukhothai World Heritage Site.

Sukhothai was the capital of the first Thai kingdom, founded around 1238. Under King Ramkhamhaeng it grew powerful, and the Thai script is said to have been created here. The ruins of its royal palace and 26 temples stand within old walls and moats, among ponds and lawns. Sukhothai Historical Park has been a UNESCO World Heritage Site since 1991.

Wat Mahathat was the main temple of Sukhothai and the spiritual centre of the kingdom. It was founded in the 13th century. Its central chedi has a lotus-bud top typical of Sukhothai style, surrounded by smaller chedis. Rows of columns that once held up the halls frame seated Buddha images. The temple is reflected in the ponds around it.

Wat Si Chum lies just north of the old city walls of Sukhothai. It holds Phra Achana, a huge seated Buddha about 15 metres high, squeezed into a square hall with no roof. A narrow slit in the front wall gives a view of the Buddha's face. A stairway hidden in the wall, lined with old carved slabs, once allowed people to reach the top.

Si Satchanalai Historical Park lies about 50 kilometres north of Sukhothai on the Yom River. Si Satchanalai was a twin city of Sukhothai and was ruled by the crown prince. Its temples include Wat Chang Lom, whose chedi is ringed by elephant sculptures. The area was also known for its kilns making celadon pottery. It is part of the Sukhothai World Heritage Site.

Wat Phra That Lampang Luang is a walled temple south of Lampang town, thought to be among the finest Lanna temples. Its golden chedi is said to hold a relic of the Buddha. The open sided main hall, built in the 15th century, has fine wooden carvings. In one building, light through a hole projects an upside-down image of the chedi onto a cloth.

Wat Phra That Hariphunchai in Lamphun was founded in 1108 by the Mon king of Hariphunchai. Its golden chedi, about 46 metres tall, is said to hold a relic of the Buddha. The temple is one of the most important in northern Thailand. Its grounds also include one of the largest gongs in the world, a library on stilts and a stepped Mon pyramid.

Wat Chedi Luang stands in the centre of old Chiang Mai. Its great brick chedi was built in the 15th century and once rose about 80 metres, the tallest structure in the Lanna kingdom. An earthquake in 1545 brought down its top. The Emerald Buddha was kept here for some decades. The chedi's stairs are guarded by naga serpents and elephant sculptures.

Wat Phra Singh is one of the most honoured temples in Chiang Mai, founded in 1345. It houses the Phra Buddha Sihing, a revered Buddha image paraded through the city during the Songkran new year festival. The small Lai Kham chapel is a fine example of Lanna architecture, with carved gables and wall paintings of daily life in old northern Thailand.

Wat Phra That Doi Suthep stands on a mountain above Chiang Mai, about 1,000 metres up. It was founded in the late 14th century. Legend says a white elephant carrying a relic of the Buddha climbed the hill and died here, and the temple was built on the spot. A staircase of over 300 steps lined with naga serpents leads to the golden chedi and a view of the city.