Decades ago, news from the outside world would pour in through the Singapore General Post Office via ships calling at the port.
Housed in the 1928 Fullerton Building, the thriving post office was well-utilised by merchants who sent out telegrams, money orders and parcels.
Mr M. Bala Subramanion, the postmaster-general who worked at the General Post Office between 1936 and 1971, said it functioned as a "hub of communication".
"All the mail that arrived in Singapore went through our sorting office. There were also petition writers who, in their private capacity, would help early migrants to fill up forms and write letters to their families," the 98-year-old said.
The National Heritage Board (NHB) gazetted the building, now home to The Fullerton Hotel, as Singapore's 71st national monument in a ceremony yesterday.
The board said the thriving post office reflected Singapore's role as the prime postal unit in British Malaya in the 20th century.
The national monument gazette is the highest form of recognition for a structure or site's significance. Evaluation factors include its historical, architectural and social importance to the Republic's built heritage.
The process involves a multi-disciplinary advisory committee which provides input to the NHB's preservation of sites and monuments (PSM) division.
Prime Minister Lee Hsien Loong, who officiated at the ceremony, said the building holds special meaning to Singaporeans, who remember it fondly as the General Post Office.
He added that he has personal memories of the place, as it was at Fullerton Square that political parties held lunchtime rallies during general elections.
"Mr Lee Kuan Yew would speak at the PAP (People's Action Party) rally, always a major event in the campaign, and he would always deliver a stirring and memorable speech, usually in the sun, sometimes in the pouring rain. My mother would sit on the balcony of the Fullerton Building and listen to him.
"When I first entered politics in 1984, I too spoke at the Fullerton Square rally," said PM Lee.
PSM director Jean Wee described the structure as "one of the most iconic colonial buildings", defining Singapore's skyline since the 1920s.
The grand neoclassical building, with its colossal Doric columns, was commissioned by the colonial government to cope with increasing volumes of mail as the trade industry grew. Government architect Major Percy Keys led the 1924-to-1928 construction project, which cost $4.75 million and involved 3.5 million bricks and 15,673 cubic m of cement.
Multiple historic events and milestones in Singapore's history have since taken place within its walls.
During World War II, it was where Lieutenant Arthur Percival informed Sir Shenton Thomas, then governor of the Straits Settlements, of the British military's decision to surrender and where the Japanese military administration department operated during the war.
Subsequently, Singapore government departments such as the Ministry of Finance were housed there.
Retired captain P.J. Thomas, 74, who was part of the Marine Department and had a first-floor office adjacent to the Singapore River in the late 1960s and 1970s, said that strong relationships were built across government departments.
"There were so many government offices there. I became friends with many of the officers," he said.
Captain Thomas added that the Singapore River was always busy.
"Lighters, motorboats and sampans ferried to shore cargo such as cement, cotton and rubber bales, and sacks of rice from the big ships out in the harbour," he said.
The Fullerton Building also once had a lighthouse which guided ships into the Singapore Harbour.
It was replaced in 1978 by the Bedok Lighthouse when its effectiveness diminished as skyscrapers rose around it.
In 1996, the Urban Redevelopment Authority conserved the Fullerton Building before it was transformed into a hotel by Sino Land - the Hong Kong arm of Far East Organization.
PM Lee said the building's transformation serves as a reminder of how far Singapore has come from a third-world country to first.
He added that the building is now part of the NHB's 8km Jubilee Walk, which features other national monuments such as the new National Gallery Singapore, the Asian Civilisations Museum and Victoria Theatre and Concert Hall.
PSM's Ms Wee said: "As we celebrate Singapore's Golden Jubilee, we reflect on the trail history has left on our landscape, and in turn accord those that are nationally significant the highest form of preservation and recognition."
The Fullerton Hotel is running an exhibition on the building's history till the end of February.
It is also selling a 160-page book, called Fullerton Stories: Rediscovering Singapore's Heritage, at its gift shop for $68.