Guided by blood ties and twists of the tongue

Tour guides are among the few experts who can decipher the hidden messages inscribed on the stone walls of the temples in Angkor Archaeological Park, the UNESCO World Heritage site in dense forest in northwestern Cambodia.

Over the past 20 years, Lam Bun Pa, 42, has explored nearly every corner of the historical sites in the country's Siem Reap Province. Lam, a Cambodian tour guide who speaks Mandarin, said that one of the most popular sites among Chinese tourists is the Bayon temple, built at the end of the 12th century.

He points to one of the carvings on its outer wall depicting a naval battle between the Cambodian ancestors of the Khmers and Chams, another ancient group from a once-powerful Hindu-Buddhist kingdom that at one stage thrived in what is now central and southern Vietnam.