KATHMANDU, Nepal — A year and a half after a colossal earthquake destroyed hundreds of treasured historic sites across this mountain nation, Nepal on Tuesday celebrated the restoration of the first major one to be rebuilt - an iconic Buddhist monument topped in gold that towers above Kathmandu.

One of the largest of its kind in the world and a major tourist attraction, the Boudhanath stupa was repaired not with government funding, but with private donations from Buddhist groups and help from local volunteers. The government has been harshly criticized for its slow pace of reconstruction and its failure to repair the vast majority of the country’s heritage zones.

Prime Minister Pushpa Kamal Dahal praised the private restoration effort in a speech at the monument, and said it should serve as an example for the rest of the nation.

It offers “proof that we can rebuild our heritage,” Dahal said. “This example puts pressure on us in government to reconstruct all the houses and temples that have been damaged.”

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Believed to have been built in the 14th century, Boudhanath was shaken by a magnitude 7.8 quake in April 2015 that devastated the nation, killing nearly 9,000 people and displacing millions. Its sprawling white dome - topped with four pairs of hypnotic eyes that stare out across the capital city - was largely spared, but the gold spire that sits atop the dome was severely damaged.

Local and foreign donors contributed more than $2 million, said Milan Bhujel, an adviser to the Boudhanath Area Development Committee, which helped organize the effort. Donors also gave 31 kilograms of gold, which covers the structure’s pinnacle, including 13 steps that represent the Buddhist path to enlightenment.

Over the weekend, a helicopter showered Boudhanath with flowers during a three-day purification ceremony that drew thousands of pilgrims who prayed, chanted and lit butter lamps. The complex, which from above resembles the Buddhist diagram of the cosmos known as a mandala, was floodlit with festive blue, red, green and yellow lights.

Ratna Bazra Lama, a 63-year-old businessman who lives at the edge of the complex, said he was ecstatic to see the stupa completed after watching it being taken apart and then left in scaffolds for months.

“I could see it from my window every day. It was so sad,” he said. “So we’re happy it’s been restored,” and fortunate, too, since most other damaged cultural sites remain wrecked.

Boudhanath is a U.N. World Heritage site, but Christian Manhart, UNESCO’s representative to Nepal, said the U.N. was not consulted on the reconstruction effort. He said U.N. experts were concerned a concrete new platform on top of the stupa might be too heavy, and they would like to study it more closely.

Nepal’s chronic political instability - 24 governments in the past 26 years - has greatly hindered rebuilding efforts. It took nearly a year for the government even to form an earthquake reconstruction authority; some 4 million people, meanwhile, spent winter homeless in the Himalayan nation.

Manhart said the reconstruction of heritage sites in the Kathmandu Valley has been “extremely slow (in part) because there’s no clear decision-making line” in government. But he also said restoring temples was painstaking work that required extensive research and testing of foundations and materials to determine the best way to rebuild.

“It’s better to do it slowly and do it well, than to do it too quickly,” Manhart said.