Thousands gathered on Rio de Janeiro's famous Copacabana beach ahead of a free open-air concert by Madonna, expected to attract 1.5 million people.
The Brazilian show on Saturday marked the end of the pop superstar' greatest hits world tour, "Celebration," which started in late 2023.
Rio's city government said it would deploy thousands of police officers around the concert area, managing the crowds with a strategy similar to its plan for the city's famous New Year's Eve celebrations.
With temperatures around 28 degrees Celsius, firefighters sprayed water to cool some fans already gathered next to the "Material Girl" singer's stage.
Drinking water was also being distributed for free.
Rio authorities expect about 1.5 million people to show up for the concert on the iconic beach, where crowds have previously exceeded 1 million for concerts by the Rolling Stones and Rod Stewart.
Madonna arrived in the city earlier in the week and fans have congregated around her hotel.
Rio's state and city governments said they spent 20 million reais ($NZ6.4 million) on the concert, while the rest was financed by private sponsors.
The authorities estimate the concert could bring about 300 million reais to Rio's economy.