Up to one million Cambodians have witnessed the relocation of Buddha relics to a new hilltop shrine near the capital Phnom Penh.
The relics - fragments of bone and a tooth - were originally moved in 1957 from Sri Lanka, the birthplace of the Theravada Buddhism practised in Cambodia.
The crowds on Thursday were so massive that the authorities were forced to airlift out the Prime Minister, Hun Sen.
But King Norodom Sihanouk presided over the ceremony to inaugurate the shrine - or stupa - at Udong, 40 kilometres (25 miles) north of the capital, after leading a procession bearing the relics from their storage place.
The site for the domed stupa, which stands 42 metres (138 feet) high and cost $4.5 million, was chosen by astrologers.
The king told the massive crowd of devotees: "The site's auspicious nature will bring to our country and people future peace, stability, happiness, constant progress and development, prosperity, grandeur and glory.''
Camped out
King Sihanouk turned down the helicopter rescue offer and waited nearly two hours for the road south to Phnom Penh to clear enough for his motorcade to pass.
The relics, kept in a golden-painted urn and locked in a glass box, had been carried in procession on top of a truck that was decorated in the form of the legendary bird Garuda.
Hundreds of thousands of Cambodians from different provinces had camped out near the hilltop the night before the procession, with monks chanting blessings and worshippers holding incense sticks and lotus flowers.
About 95% of Cambodians are Buddhists.
Excited schoolchildren and factory workers who were given the morning off for the occasion lined the road to cheer the procession.
One Phnom Penh resident, Chhorn Maly, 64, was up at 0200 to be in time to join the head of the procession from the capital.
''Nothing is more important than putting your faith in Buddha,'' she said, recalling a similarly large ceremony in 1957 to mark the arrival of the remains from Sri Lanka.
Khim Bo, deputy governor of Kandal province, said the ceremonies at Udong, which were broadcast nationwide on television and radio, would continue for three days and there would be firework displays at night.