Inacio Lula da Silva has been sworn in as the new president of Brazil - the
third time he has held the country's highest office.
The veteran left-wing politician, known widely as Lula, also led the country between 2003 and 2010 - and defeated Jair Bolsonaro in October's poll.
In his first speech, Lula vowed to rebuild a country in "terrible ruins".
He decried the policies of his predecessor, who went to the US on Friday to avoid the handover ceremony.
A sea of Lula supporters gathered in front of Congress since early in the morning - decked out in the red colour of his Workers' Party. They travelled to see their leader sworn in - but also for a celebration.
More than 60 artists - including Samba legend Martinho da Vila - were booked to perform on two giant stages decorated in the national flag as part of a music festival dubbed "Lulapalooza".
"Love has won over hate," read one banner carried by a man dressed as Lula - complete with a presidential sash.
"Brazil needed this change, this transformation," said another backer of the incoming leader as she queued for Sunday's festivities.
Juliana Barreto - who is from Lula's home state Pernambuco - told the BBC that her country was "a disaster" previously.
Lula and incoming Vice-President Geraldo Alckmin paraded through the city on an open-top convertible before proceeding to the Congress building - where the swearing-in occurred at the start of the formal inauguration ceremony.
The men have spent the past days selecting their cabinet and appointing supporters to key state-owned businesses.
Shortly after being sworn in, Lula sought to instil a sense of hope in the people of Brazil and promised to "rebuild the nation and make a Brazil of all, for all".
There were several instances when he got out his hanky. His most emotional moment came when speaking to the Brazilian people after the swearing-in ceremony - he started sobbing when talking about those who beg at traffic lights, desperate for food.