By David Willey, BBC's Rome correspondent
In Istanbul, we have, I believe, witnessed some defining moments of the papacy of Benedict XVI.
He reached out to Muslims by praying facing towards Mecca in a famous mosque.
And he reached out to Orthodox Christians, seeking to heal a rift that has lasted more than 1,000 years by holding joint services and giving a joint blessing to their faithful by the side of Patriarch Bartholomew, their spiritual leader, on the holiest day in their church calendar.
The Pope won the praise of Turkey's former religious affairs director Mehmet Nuri Yılmaz for facing Mecca when he prayed in silence inside Istanbul's Blue Mosque.
Benedict closed his eyes and moved his lips in prayer for what seemed like two very long minutes after being shown around this famous gem of 17th-Century Ottoman architecture.
The moment was "even more meaningful than an apology" for the Pope's much criticised remarks about the Prophet Muhammad in September, said the Mufti of Istanbul, Mustafa Cağrıcı, the Pope's guide during the visit.
The religious and historical symbolism of the Pope's journey to Istanbul has been striking.
One of its dominant monuments is the broad-domed former Christian church of Hagia Sophia, built by the Roman Emperor Justinian 1,500 years ago.
For centuries this was the largest church in the world. After the fall of Constantinople in 1453, Hagia Sophia became a mosque; now it is a museum.
Yet a prayer here would have been considered out of place.
It would have offended his hosts, the government of the secular Turkish state.
Benedict respected protocol. But 10 minutes later, under the glare of television lights, he was praying at the side of an imam inside the Blue Mosque, only 500 metres away from Hagia Sophia.
It's been a historic week.
Speaking on US TV, he said conflicts in Lebanon, Iraq and the Palestinian territories could spin out of control.
Abdullah hosted both the US president and the Iraqi prime minister for talks against a backdrop of escalating violence in Iraq last week.
King Abdullah said the central issue in the region remained the Israeli-Palestinian conflict.
"Palestine is the core," he said. "It is linked to the extent of what's going on in Iraq."
"It is linked to what's going on in Lebanon. It is linked to the issues that we find ourselves with the Syrians. So, if you want to do comprehensive - comprehensive means bringing all the parties of the region together."
A ceasefire between Palestinian militant groups and the Israeli military is currently in place in Gaza.
Peace is Better
By Alan Johnston, BBC News, Gaza
After five months of hostilities, Palestinian militants and the Israeli army agreed a ceasefire in the Gaza Strip at the beginning of this week and the truce appears to be holding. People are now hoping this might open the way for the peace process to resume.
I found a man called Mohammad Adwan sitting in a plastic chair on Hamad Street. He was chatting to his wife and children, and enjoying the unexpected peace.
Plastered to the wall above them was a photograph of Mohammad's brother. He was killed on Hamad Street three weeks ago in an Israeli artillery barrage.
He had been trying to rescue his neighbours as the shells crashed down. Nearly 20 people were killed in what the army said was a mistaken, misdirected attack.
All of them were civilians.
Mohammad Adwan said simply: "Our children are scared, and their children are scared. To live in peace is better."
To almost everyone's dismay, in those first hours the new truce was threatened briefly by another volley of missiles from the Palestinian side.
"That's enough with the rockets," said Mohammad wearily. "That's enough."
People here know the rhythms of the politics of the Middle East all too well. They do not really believe that the calm will last.
But right now there is something very unusual in the air in Gaza - there is the faintest sense of hope.
Meteorite yields life origin clue
Scientists say that "bubbles" like those in the Tagish Lake meteorite may have helped along chemical processes important for the emergence of life.
The globules could also be older than our Solar System - their chemistry suggests they formed at about -260C, near "absolute zero".
Details of the work by Nasa scientists are published in the journal Science.
Pictures courtesy of BBC News online.