PHNOM PENH, Cambodia-Tens of thousands of spectators flocked to the riverside in Phnom Penh on Sunday for an 838-year-old boat racing tradition, held to celebrate the annual three-day Water Festival.

Viewers, mostly from the countryside, gathered on both sides of the Tonle Sap River to cheer on boatmen, dressed in T-shirts, as they raced their dragon boats along a 1.7-kilometer stretch of the river that passes by the front of the royal palace.

Lonh Davan, 18, a native of southeastern Tboung Khmum Province, said she has never lost her excitement watching boat racing, although she has seen it many times.

"I feel very happy to see people from everywhere come to see the Water Festival," she said. "Moreover, this event has brought me to an ancient time when our marine forces used boats to wage war against the invading enemies."

Bou Chumserey, vice-chairman of the boat-racing technical control committee, said a total of 291 dragon boats with 19,218 oarsmen from various provinces are participating in the Water Festival.

He said boats are competing in different categories depending on the number of boatmen.

"The festival is to remember the strength of the powerful Khmer marine forces during the ancient Khmer Empire in the late 11th century," he said.

He said during the reign of Angkorian King Jayavarman VII, the king had used naval forces, with boats as transport means, to fight against the invading Chams and defeated them in 1181.

The event is also to mark the end of the annual rainy season and the rare reversal of flow of the Tonle Sap River that connects the Tonle Sap Lake with the Mekong River.

"The Water Festival is also to express our gratitude to the Mekong River for providing us with water, fertile land and abundant fish," he said.

Cambodian King Norodom Sihamoni, along with Prime Minister Hun Sen, presided over the opening ceremony of the festival on Sunday afternoon. The king will again attend the closing ceremony on Tuesday evening.

A team leader of a racing boat from Central Kampong Thom Province, Lun Chhon, 55, said his boat has 73 rowers.

"The Water Festival is to remember the powerful naval forces in the ancient time who used boats to chase away the enemies," he said. "Our participation is to preserve our age-old tradition."

Chea Chhuon, a team minder of a 44-man dragon boat from southern Kandal Province, said: "We celebrate this festival to show our thanks to the Mekong River for providing water for animals, plants and humans," the 44-year-old man said.

The Water Festival is one of the largest annual festivals celebrated in the Southeast Asian nation. Apart from viewing the races during the day, festival-goers can enjoy the procession of illuminated floats and fireworks as well as concerts at night.