Officials in Brazil have blamed lack of funding for a huge fire that has ravaged the country's National Museum.
One of the largest anthropology and natural history collections in the Americas was almost totally destroyed in Sunday's fire in Rio de Janeiro.
There had been complaints about the dilapidated state of the museum. "We never had adequate support," its deputy director said after the fire.
Presidential candidate Marina Silva also criticised lack of investment.
"Given the financial straits of the Federal University of Rio de Janeiro and all the other public universities the last three years, this was a tragedy that could be seen coming," Ms Silva, a left-wing politician standing in next month's election, tweeted.
The fire started on Sunday evening, after the building – a 19th-Century former royal palace – had closed for the day. The cause is not known.
No injuries have been reported, but most of the 20 million items the museum contained, including the oldest human remains ever found in the Americas, went up in flames.
Brazil's President Michel Temer said in a tweet that it was a "sad day for all Brazilians" as "200 years of work, research and knowledge were lost".
A deputy director at the museum, Luiz Fernando Dias Duarte, expressed "immense anger", and accused Brazilian authorities of a "lack of attention."
One employee told Globo TV that project managers had had "tremendous difficulty" trying to secure funding for "sufficient" resources for the building.
A third of the 30 exhibition halls were closed because of budget cuts, the Folha de Sao Paulo newspaper says.
A major dinosaur exhibition, which was forced to shut following a termite attack five months ago, recently reopened only thanks to a crowd-funding campaign, the report adds.
Museum librarian Edson Vargas da Silva told local media that the building had wooden floors and contained "a lot of things that burn very fast", such as paper documents.
The museum, Brazil's oldest, is managed by the Federal University of Rio de Janeiro and the federal government has been struggling with huge budget imbalances in recent years.
The deficit was about 8% of GDP in 2017, only slightly down from a record 10% two years earlier.
But Rio de Janeiro state is also facing a budget crisis.
Roberto Robadey, a spokesman for the Rio fire department, is quoted by the Associated Press news agency as saying that the hydrants closest to the museum were not working and that firefighters had to get water from a nearby lake.
By Katy Watson, BBC South America correspondent
This isn't just Brazilian history that's gone up in flames. Many see this as a metaphor for the city – and the country as a whole.
Rio de Janeiro is in crisis. Growing violence, a deep economic decline and political corruption have combined to make the city a shadow of what it once was. It was only in 2016 that it was hosting the Olympic Games – an event into which Brazil poured billions of dollars.
But the hangover from the sporting event has hit Rio hard. Add to that the fact that federal spending has been slashed, and with violence on the rise, tourism numbers have also declined.
This was a museum that many saw as long ignored and underfunded – now, with devastating consequences for Brazil's heritage.
Its 20m artefacts included fossils, Brazil's largest meteorite, dinosaur bones and a 12,000-year-old skeleton of a woman known as "Luzia", the oldest ever discovered in the Americas.
The building was also home to items covering the centuries from the arrival of the Portuguese in the 1500s to the declaration of a republic in 1889.
The ethnology collection had unique pieces from the pre-Columbian era and artifacts from indigenous cultures.
Pieces from Greco-Roman times and Egypt were also on display at the museum.
Portugal's royal family transferred the court to the building in 1808, when the country faced the threat of invasion from Napoleon.
The museum was established in 1818, with the aim of promoting scientific research by making its collection available to specialists.