Pope on a boat!: Francis visits Venice and is seen enjoying a canal tour after ... trends now

Pope Francis has visited Venice and took part in a canal tour weeks after asking worshippers to 'pray for him' following a health battle.

The head of the Catholic Church appeared in good spirits in the Italian city on Sunday as he was welcomed to the city by roaring crowds of people.

The 87-year-old was seen smiling as he visited an art exhibition which was being held inside a women's prison and talking to female inmates who had their artworks on display.

He also took part in a trip to Saint Mark's Basilica in the centre of the city, before holding mass outside in St Mark's Square where he told the crowds his job was 'not easy.

Francis's Sunday morning visit represented an increasingly rare outing for the 87-year-old, who has been endured health and mobility problems that have ruled out any foreign trips so far this year.

In March he had unexpectedly withdrawn from a Good Friday procession to 'preserve his health', after battling respiratory problem all winter which have made it difficult for him to speak.

That last-minute decision had raised questions about how long Francis can continue to lead the Catholic Church, although he appeared to be in much better form in Venice on Sunday.

Venice, with its 121 islands and 436 bridges, isn't an easy place to negotiate, but Francis pulled it off, arriving by helicopter from Rome, crossing the Giudecca Canal in a water taxi and then arriving in St. Mark's Square in a mini popemobile that traversed the Grand Canal via a pontoon bridge erected for the occasion.

During an encounter with young people at the iconic Santa Maria della Salute basilica, Francis acknowledged the miracle that is Venice, admiring its 'enchanting beauty' and tradition as a place of East-West encounter, but warning that it is increasingly vulnerable to climate change and depopulation.

'Venice is at one with the waters upon which it sits,' Francis said. 

'Without the care and safeguarding of this natural environment, it might even cease to exist.'

However, the trip was also unusual because it came as Venice, sinking under rising sea levels and weighed down by the impact of over-tourism, is in the opening days of an experiment to try to limit the sort of day trips that Francis undertook on Sunday.

Venetian authorities last week launched a pilot programme to charge day-trippers 5 euro (£4.20) apiece on peak travel days. The aim is to encourage them to stay longer or come at off-peak times to cut down on crowds and make the city more liveable for its dwindling number of residents.

For Venice's Catholic patriarch, Archbishop Francesco Moraglia, the new tax programme is a worthwhile experiment, a potential necessary evil to try to preserve Venice as a liveable city for visitors and residents alike.