Provincial authorities and residents in the lower northeastern province of Buri Ram are confident Phanom Rung Historical Park, also known as Prasat Phanom Rung, and two nearby ancient sites will soon be declared Unesco World Heritage sites.
Unesco's World Heritage Committee (WHC) agreed to add Phanom Rung Historical Park, Prasat Muang Tam and Prasat Plaibat in Chalerm Phrakiat district to its "tentative list" of cultural world heritage sites last year, says Buri Ram governor Thirawat Woottikhun.
The WHC suggested Thailand prepares documents for the next step in the process of listing them.
Mr Thirawat said he is confident the three castles will be accepted into the site list as they are unique. Many worshippers go up to Prasat Phanom Rung, located at the rim of an inactive volcano, to make merit.
Mr Thirawat said these rites were influenced from ancient Khmer art and culture that have passed on from generation to generation.
"Some local villagers still carry on these activities, particularly a religious ceremony to bring in nam mon, or holy water, from the rites to pour onto Shiva Linga," he said.
Every year sunshine passes through through all 15 doors of the Prasat Phanom Rung's main tower. The beautiful solar phenomenon occurs only four times a year, from March 5 to 7 and Oct 5 to 7 for sunsets or from April 3 to 5 and from Sept 7 to 9 for sunrises, he said.
The spectacle is accompanied by a series of rituals and processions in honour of the gods and cultural performances. Many visitors go there to take photos, he said.
"It's such a spectacular phenomenon," Mr Thirawat said. "This castle is regarded as a triumph for geographic architecture for the time. Architects calculated accurately the time when the sunshine would beam through all the doors.
"I am sure these factors will help Prasat Phanom Rung and its nearby castles be declared as Unesco World Heritage sites."
Once the castles are listed, the lower northeastern province will reap benefits from tourism.
It is expected their preservation will be upgraded to world standards for historical parks and ancient remains. More tourism–related development projects would be drafted with more funds allocated, he said.
Phanuwat Ueasaman, head of the Phanom Rung Historical Park, said a local committee has prepared documents for the next step in the process of listing the three castles as Unesco World Heritage sites, and they will be submitted to the WHC for consideration soon.
Mr Phanuwat said a nomination dossier is being prepared by the Buri Ram provincial authorities in cooperation with Phanom Rung Historical Park officials. After that it will be submitted to the government through the Fine Arts Department of the Ministry of Culture before it is passed on to the WHC, he said.
Mr Phanuwat said Prasat Phanom Rung is different from other historical sites in the country. "For its style of construction and use in religious rites which were organised on the mountain top which was once an active volcano, it shows off local wisdom regarding architecture," he said.
Phanom Rung Historical Park has been categorised as an ancient monument site in the same group or cluster for religious places which consist of the three historical remains.
They are the Prasat Phnom Rung, Prasat Muang Tam, and Prasat Plaibat castles. The three sites are situated in compounds with a radius of 4-8 kilometres.
"Once they are declared as new World Heritages sites, I am sure this will bring in great benefits to the country," Mr Phanuwat said.
"The construction of high-rise buildings near these sites will not be allowed.
"There will be no such buildings that will block views from these sites."
He said foreign tourists are also expected to visit these historical sites which will bring in more income to local villages.
Last year 841,811 people visited Phanom Rung Historical Park and its nearby castles.
Nearly 18,000 of them were foreigners.
Meanwhile, Chotima Yimchuen, 53, a local villager from Prakhon Chai district, said she has been selling local products and souvenirs at the foot of Phanom Rung Mountain for more than 30 years.
She said she has made ends meet from selling clothes, earthenwares and other local products.
She finds time to do this when the rice farming season is over.
"I will feel glad and proud like other villagers around here, if Prasat Phanom Rung and its two nearby castles are announced as Unesco World Heritage sites," Ms Chotima said.
"They and areas around them will be more well-known with big crowds of visitors."
She said she also hoped the government will have more projects to help develop the quality of life for local people here.
"Today I earn about 1,000 baht daily from my two small shops. In the future, I may earn more than this from the tourist-related development projects," she said.