Pope Francis can expect a warm welcome from hundreds of thousands of young Catholics when he arrives in Poland for the a five day visit to World Youth Day in Kraków.

According to Crux, Kraków will be a feast of visual pageantry, culminating in a Saturday evening vigil and Sunday morning Mass with the Pope which will rival Broadway and West End productions of Cats and Evita for music, show and style.

Many youths, such as the young people at the festival's 'eco village', are waiting eagerly to meet him. But before he can relax into the friendship, Bible studies, pastoral visits and prayer that he loves so much, the Pope's first duty is at Wawel Castle where he will make a speech to an audience of diplomats and local dignitaries. He will also meet the devoutly Catholic President Andrzej Duda in private.

Poland is economically dependent on its coal industry. Many Polish leaders will be seeking reassurance from Pope Francis about his encyclical on the environment, Laudato Si, which calls for limits on the use of fossil fuels.

The festival, which by its end will see more than 1.5 million young people in and around Kraków, is the biggest media event in Poland for decades, if not in its entire history, with thousands of journalists accredited.

Some of the young people attending are keeping video diaries for the BBC.

In the opening Mass, Kraków Cardinal Stanislaw Dziwisz, former secretary to St Pope John Paul II, called on young Catholics to read a "message of divine mercy".

The Cardinal, who is expected to retire soon - leading to speculation that the Pope will use some of his time in Poland to sound out bishops and senior laity about his successor - said according to the Catholic News Agency: "We come from every nation under heaven, like those who came in great numbers to Jerusalem on Pentecost Day, but there are incomparably more of us now than 2000 years ago, because we are accompanied by centuries of preaching the Gospel."

Cardinal Dziwisz continued: "We bring experience of various cultures, traditions and languages. But what we also bring are testimonies of faith and holiness of our brothers and sisters, followers of the risen Lord, of past generations as well as the current generation."

In spite of heavy rain, there were  about 200,000 pilgrims from 187 countries in Kraków's Blonia Park. Nearly 50 cardinals, 800 bishops and 20,000 priests from around the world are expected to be at World Youth Day this week.