THE discovery of a hundred never-before-seen paintings of deities, animals and musical instruments on the walls of Cambodia's Angkor Wat excited archaeologists worldwide when details came out in a journal last month.
The paintings, which cannot be seen by the naked eye, speak of a time when the Unesco World Heritage site underwent a transformation from a Hindu temple to a Buddhist one under 16th century leader King Ang Chan.
The man behind what experts call a "significant discovery" is a Singaporean: 35-year-old Noel Hidalgo Tan, who stumbled upon the markings in 2010 while volunteering at an excavation project at the 12th century site.
He was wandering around the temple during his lunch break when he spotted patches of faint red pigment in the chambers of the temple's uppermost tier.
He took photos of the spots as they looked similar to the prehistoric markings he had seen in South-east Asian caves - his main area of research as a final year PhD student at the Australian National University (ANU).
But he did not know he was on to something special. "It's a site that thousands of people pass by every day and hundreds of researchers have worked on. I didn't think it was something new and unexplored," he said.
Comprising 900-year-old towers, a large moat and bas-relief carvings of Hindu gods, Angkor Wat is one of the largest religious monuments in the world and features on Cambodia's national flag.
It was only in 2012, when Mr Tan showed the markings to Cambodian researchers, that he realised their significance.
Mr Tan then ran the images through the DStretch programme, which plays up colour differences and helps to distinguish between similar shades of colours.
He dedicated the next four months or so to analysing the paintings and setting them in the context of Angkor Wat's history, alongside archaeologist Im Sokrithy from the Authority for the Protection and Management of Angkor and the Region of Siem Reap (Apsara).
Mr Sokrithy, also head of communications at Apsara, said researchers have known of the existence of most of these paintings. "But we have not had the technology to document them in such detail and with such clarity."
The duo put out a paper on the subject earlier this month in Antiquity, a quarterly archaeological research journal.
It made waves in the archaeology community and Mr Tan's findings have been featured in international publications such as Time, Smithsonian and the Daily Mail.
The paper details the hundred newly discovered paintings and another hundred markings which Mr Tan documented. He grouped these paintings into five themes.
The paper notes that the paintings comprise a mixture of graffiti by pilgrims and visitors from the 16th century to the recent past and commissioned work by King Ang Chan and his successors.
The graffiti reflects everyday life and depicts, for instance, buildings and livestock such as horses. The commissioned drawings, distinguished by their schematic and elaborate nature, reflect a time when the temple was converted from a Hindu one to a Buddhist one. They include drawings of Buddhist stupas and Buddha meditating.
Experts, such as archaeologist Damian Evans of the University of Sydney, say the findings show there is still a lot to be learnt at historic sites which welcome millions of visitors every year.
But Mr Tan is leaving the images he processed and his findings at Angkor Wat to other scholars.
Apsara, for instance, hopes to build on the interest generated by Mr Tan's findings and is looking into ways to preserve and present the paintings to visitors.
Said Mr Tan: "I believe that there's more to be learnt about these 15th century paintings... like from maritime academics on the types of ships that were depicted in the scenes.
"I'm leaving my findings in the good hands of my colleagues."
Mr Tan had stumbled upon the intricate pictures at Angkor Wat; likewise, he had uncovered a love for digging up the past by chance.
As a fresh mass communications graduate from Ngee Ann Polytechnic in 2003, the elder child of a teacher and office manager wanted to go for further studies but was unsure of what to pursue.
He was inclined towards a double major in political science and economics. But an interview with a curator from the National Museum of Singapore, for a career guide he helped put together for The Straits Times' Classifieds in 2003, set him on a different path.
The conversation kindled his interest in the field and led him to volunteer at an excavation effort at St Andrew's Cathedral.
The thrill of digging up ceramic pieces that go back centuries alongside fellow diggers cemented his path as an archaeologist. "It's quite humbling when you realise the pieces that you dig up are hundreds of years old," said Mr Tan.
That prompted him to pursue archaeology and political science at the University of Melbourne. He then did a Master of Arts in archaeology at the Universiti Sains Malaysia before embarking on a doctorate at ANU. After he completes his PhD, Mr Tan, who is single, plans to continue researching South-east Asian rock art.
He is still surprised by the impact his findings at Angkor Wat has had globally. The discovery is "immensely rewarding", he said.
"Such discoveries are what we live for and what drive us as archaeologists."