Many thousands flock to hear Pope Benedict in Croatia
Pope Benedict XVI has celebrated Mass, focusing on family values, before tens of thousands of people in the Croatian capital, Zagreb.
He spoke of the "disintegration" of the family, and urged couples not to give in to a "secularised mentality" of living together instead of marrying.
He later visited the tomb of a controversial wartime cardinal.
This is Pope Benedict's first visit to the staunchly Catholic nation and he has received a warm welcome.
Upon his arrival on Saturday, the Pope gave his backing to Croatia's bid to join the European Union.
He said he understood fears of a loss of cultural identity by joining the EU, but said Europe needed reminding of its Christian roots.
"From its beginning, your nation has belonged to Europe," he said as he arrived at the airport.
As many as 400,000 people from across Croatia and neighbouring countries were thought to have attended Sunday's open-air Mass at Zagreb's hippodrome.
The Pope, whose visit was timed to mark Croatia's Family Day, spoke out against practices such as abortion and called on citizens to back legislation that supports families in "the task of giving birth to children and educating them".
After the mass, Pope Benedict prayed at the tomb of Cardinal Alojzije Stepinac.
Many Croatian Catholics regard Stepinac as a hero who, they say, spoke out against the Nazi-backed regime during WWII and later refused to bow to the communist rulers of Yugoslavia.
But critics say he did not sufficiently condemn the persecution of Serbs and Jews by the Nazis.
The late Pope John Paul II caused controversy when, during a visit to Croatia in 1998, he put Cardinal Stepinac on the road to sainthood.
Pope Benedict on Saturday praised the cardinal's "real humanism", but he did not say whether he would be proclaimed a saint.
At the start of his visit, the Pope met Croatian President Ivo Josipovic, before addressing a gathering of academics, cultural, business and diplomatic leaders.
On Saturday evening, he led a prayer vigil for some 25,000 young Croats in Zagreb's main square.