One of Rio de Janeiro's leading samba schools has shone a spotlight on a Brazilian mining disaster at this year's carnival.
The Portela school used one of its floats to interpret a 2015 dam failure in Minas Gerais state.
Nineteen people were killed and hundreds of homes were destroyed in the mudslides in the Mariana area.
Portela's carnival float featured the giant figure of fisherman, crying out in distress over pollution.
Other members of the troupe walked alongside, carrying placards with emotive messages such as "Sadness", "Justice" and "SOS".
Thousands of fishermen sued the Samarco iron-ore mine for loss of earnings after the dam collapse saw millions of tonnes of toxic waste flow into nearby rivers and on to the Atlantic Ocean.
The two firms behind the mine, Vale and BHP Billiton, have been ordered to consolidate and settle compensation claims by the end of June this year.
The Portela school chose an overarching rivers theme for all its floats this year and paraded through Rio de Janeiro's Sambadrome in the early hours of Tuesday morning.
Brazil's Globo newspaper said the atmosphere was tense when Portela's show began, as it followed a performance by the Unidos da Tijuca school. The the top of its float collapsed and dancers were thrown from a raised walkway.
However, Portela carried on and are now among the favourites to win the competition, which sees each school parading in turn in front of a panel of judges.
Brazil's carnival is often associated with frivolity, but the parade often carries deeper meanings and can cause controversy.
This year, the Imperatriz Leopoldinense samba school themed its entry on land rights of indigenous people, which was interpreted by some as an attack on agricultural businesses.
Brazil's Association of Cattle Breeders said in a statement: "It is unacceptable that the most popular Brazilian festival, which has the admiration and respect of our sector, should stage a show of sensationalism and unfounded attacks."
Ahead of the parade, indigenous leader Alessandra Munduruku told the Reuters news agency: "We will make carnival a political event until the attacks on us and our way of life are stopped."