Hundreds of thousands of people camped out overnight in the Ecuadorean capital, Quito, in wind and rain to secure a spot to see Pope Francis celebrate Mass on Tuesday.
The Pope is on the first leg of a three-country tour which will also take him to Bolivia and Paraguay.
On Monday an estimated 800,000 people attended the Mass Pope Francis celebrated in the city of Guayaquil.
It is his second visit to the region since becoming pontiff in 2013.
Pope Francis, who is from Argentina, has drawn huge crowds on his visits to the continent.
In 2013 three million people were estimated to have attended a Mass he celebrated on Copacabana beach in Brazil.
A Vatican spokesman said about half a million faithful lined the streets of Quito on Sunday, when the Pope arrived in the Andean country.
A Quito official said more than 300,000 people spent the night at the Bicentennial Park in Quito waiting for the Pope to celebrate Mass.
The official said more than 20 people had to be treated for hypothermia after a torrential downpour.
Abel Gualoto, a 59-year-old seafood vendor, told the Associated Press news agency that “the joy at seeing the Pope gives us the warmth we need”.
Later on Tuesday, Pope Francis is due to tour the Church of the Society of Jesus, one of the oldest and most ornate in Ecuador.
On Wednesday, he will fly to La Paz in Bolivia.
Concerns have been voiced that he could suffer from altitude sickness upon his arrival at the airport of El Alto, which lies at a height of 4,000m (13,100ft) above sea level.
Pope Francis had part of one lung removed after an infection when he was a child.
One of the symptoms of altitude sickness is shortness of breath.
According to Bolivian Culture Minister Marko Machicao, Pope Francis has requested to chew coca leaves while in Bolivia.
Coca leaves, the raw ingredient for cocaine, are used to combat altitude sickness.
The pontiff will not be travelling to his home country of Argentina on this trip, as according to the Vatican he wants to focus on some of the smaller and poorer countries of the region.
In September Pope Francis will travel to Cuba ahead of a trip to the US.
The pontiff is credited with helping to bring about last December’s diplomatic thaw between the two countries.