Pope Francis concluded his four-day pastoral visit to Colombia on Sunday by celebrating an open-air Mass in the port zone of Cartagena at which he affirmed that the people must be involved in the peace process to help the country recover from its decades-long armed conflict with the FARC and other guerrilla groups.

Before hundreds of thousands of the faithful in the tourist city's port zone, Francis waited for his final public remarks in Colombia before providing a more political analysis of the country's peace process after the peace agreement reached between the government and the Revolutionary Armed Forces of Colombia (FARC), the latter of which has now transformed itself into a political party, and the ongoing peace talks with the other large guerrilla organization, the National Liberation Army (ELN).

The pontiff also addressed the heavy polarization among Colombian society in his homily.

He advised all parties not to sidestep the people in working to ensure that the peace process takes full hold, noting that peace is not achieved merely "by designing ... frameworks and institutional arrangements between political and economic groups of goodwill" but rather by including the public in the effort.

He said that peace cannot be built by "a few for a few, or a ... minority." He also emphasized that, in addition to dialogue, "the deep wounds of history necessarily require instances where justice is done, they provide the possibility for the victims to know the truth, the damage to be ... repaired and clear actions taken to avoid the repetition of those crimes.

The pontiff also exhorted Catholics what they must do to contribute to the peace process, saying that they must "bring about cultural change from below: the culture of death, of violence. We must respond with the culture of life, of encounter."

At the Cartagena Container Terminal, where he celebrated the Mass, the pope emphasized that stable and lasting peace in Colombia is brought about by guaranteeing "the common good, equity, justice, respect for human nature and its requirements."

Francis also harshly condemned the social scourge of drug trafficking, saying that "this evil directly works against the dignity of the person, progressively breaking the image that the Creator has molded in us."

"One must neither toy with the lives of our brothers nor manipulate their dignity," he said, calling upon the government and the public to find the way to end drug trafficking, which "sows only death ... curtailing so many hopes and destroying so many families."

After the Mass, but before leaving Colombia, the pontiff delivered a final message, saying "Colombia, your brother needs you, look to meet him with the embrace of peace, free of all violence, slaves of peace forever."

Francis then traveled to the Cartagena airport, where he was to be officially bade farewell by President Juan Manuel Santos.

Earlier in the day, the pontiff looked the "other" Cartagena in the eye on Sunday, the one that does not appear in the tourist guides, when he visited the poverty-stricken neighborhood of San Francisco de Asis in this Colombian coastal and tourist city.

The San Francisco district began to take shape in 1963 on the edge of a swamp behind the Rafael Nuñez International Airport, and since then its residents have known virtually nothing except poverty and tragedy, but on Sunday they experienced what may have been the most hope-filled day of their lives with the visit of the Bishop of Rome.

It was a day of celebration and festivities, with the public uplifted by the presence of the smiling Argentine pontiff bearing the neighborhood's name, and Francis spent half an hour blessing the massive crowd.

Cartagena, Colombia's tourist mecca, is also one of the country's most unequal cities where some 60 percent of the public lives in poverty, one of the highest levels in the South American nation.

Even earlier on Sunday, Francis had received a warm sendoff from a huge crowd who turned out to bid him farewell as he left Bogota, boarding the popemobile at the Apostolic Nunciature and heading to the Catam military base, where his jet took him to Cartagena on the last day of his four-day pastoral visit to Colombia.

Some 4,000 police officers and 1,000 marines were tasked with providing security for the pontiff's visit to Cartagena, where he will celebrate an open-air Mass expected to be attended by some 280,000 people.

During his tour of San Francisco, the pope hit himself on the eyebrow and in the left cheek as he was trying to greet a child during his tour in the popemobile.

"The pope is fine" but he suffered "a bruise on his cheekbone and eyebrow," said Vatican spokesman Greg Burke, adding that Francis has bumped his head on the popemobile and received an ice pack to treat the resulting purple bruise.