Singapore is holding nationwide events to mark 50 years since it became an independent state.
Tens of thousands of people are expected to attend an outdoor parade, complete with flybys by the air force and a Singapore Airlines A380 airliner.
Singaporeans are also being asked to join together in reciting the national pledge and singing the national anthem.
Singapore became independent when it was ejected from the Federation of Malaya amid social unrest.
In 50 years, the former British colony has transformed itself into one of the world’s wealthiest countries.
But its critics say the rapid development has been accompanied by a strict control on free speech and politics.
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The city state celebrates its independence day in style every year, but this year’s SG50 events are being billed as the country’s biggest ever celebration, with months of build-up in shops, schools, work places and in the media.
One student, Yang Jie Ling, told Reuters: “It’s only 50 years for a small nation like us, so we have achieved so much. It’s a year that Singaporeans will want to remember forever.”
The parade this year will include a special tribute to Lee Kuan Yew, who led Singapore into independence and was its prime minister until 1990.
The much-respected leader died in March this year, prompting public mourning.
A recording of him reading the Proclamation of Independence will be played on radio at 09:00 (01:00 GMT).
Key figures attending Sunday’s celebrations include Malaysian PM Najib Razak and Australian Deputy PM Warren Truss.
Despite achieving such goals as 90% home ownership and per capita GDP above $56,000, critics continue to point to the strict political controls.
The ruling People’s Action Party (PAP) has been in power for more than 50 years and the opposition hopes to make more inroads in elections that could be called in September.
The last election saw the PAP suffer its worst performance, though it still kept 80 of the 87 seats.
It will hope the boost of the anniversary and recognition of the legacy of Lee Kuan Yew will help it at the next election.
Analysis: Tessa Wong, BBC News, Singapore
The National Day Parade is a chance for tiny Singapore to flex its military muscles and also celebrate its sovereignty – never mind that independence was unplanned thanks to its ejection from Malaysia.
The event usually features a military march past with fighter jet displays, large-scale performances by community groups, and a retelling of Singapore’s history. It ends with a massive firework display as the country recites the pledge and sings the national anthem.
In its early years, organisers used it to push social messages such as courtesy and diligence.
These days it’s a more sophisticated, glitzier affair, held by the shiny skyscrapers of Singapore’s Marina Bay.
Though the propaganda still gets heavy, Singaporeans love it anyway for its pomp and splendour. Tickets for the parade and its rehearsals run out every year.