BBC
Prince Charles has seen at first hand the devastation caused in the earthquake-hit city of Bam in Iran.
Charles toured the city, meeting survivors of the earthquake that killed an estimated 42,000 people and injured more than 30,000 on 26 December.
He was the first British royal to visit Iran since the 1970s.
The Prince of Wales has now flown to Riyadh in Saudi Arabia, but earlier gave his condolences to the Iranian President Mohammad Khatami in Tehran.
Their meeting was "warm and cordial", according to one of his aides.
My people in Britain are very concerned and they're praying for the Iranian people
Prince Charles
The two men discussed the prince's visit the previous day to neighbouring Iraq.
The president spoke of "the need for a free election [in Iraq] under UN supervision".
But Clarence House insisted the purpose of Charles' trip was humanitarian.
Andrew Dunn, of the British Embassy in Tehran, said before the visit: "Prince Charles is patron of the British Red Cross and he is coming in that role."
Arriving in Bam, Charles toured the rubbish-lined streets, watched by local people from the tents where they have lived since the earthquake demolished their homes.
He said: "My people in Britain are very concerned and they're praying for the Iranian people."
Charles also visited a date orchard and met farmers trying to rebuild the ancient underground irrigation structures, the Qanat.
His visit to Saudi Arabia comes as relations with the UK are starting to improve.
They had gone through a rocky period after a number of Britons were imprisoned over allegations of making explosions, and the kingdom was criticised for its lack of action over Islamist militants.
Charles knows the Saudi ruling family well and is considered ideal for the role of helping to build on warming relations.
Iranian Red Crescent International Affairs director Mostapha Mohaghegh said 200,000 people would need help in the earthquake's aftermath in the years to come.
During the earlier visit to Iraq on Sunday - the first by a British royal since the nation was created in 1919 - Prince Charles met troops working to restore stability in the aftermath of the war.
He also met Paul Bremer, the US top administrator in Iraq."
And an article on the possible wider implications of the trip from the BBC:
" The visit by Prince Charles to Iran - the first by a member of the British Royal Family to the 25-year-old Islamic republic - has political implications whatever the protestations of diplomats.
All official visits abroad by the Royal Family are cleared and many are proposed by the Foreign Office.
The detailed and often delicate negotiations about them are usually revealed in files which are released by the National Archives after 30 years.
This visit will have been through the same process.
So one can discount the dutiful comment of a British diplomat in Tehran who said: "Prince Charles is patron of the British Red Cross and he is coming in that role. It's a completely non-political visit."
In this case, it is true that Prince Charles's interest in Islamic history and architecture has proved the incentive for a visit to the destroyed ancient city of Bam, which was hit by an earthquake in December.
It is also true that the Prince of Wales is unlikely to have got into political discussions with Iranian President Mohammad Khatami on whom he called on Monday.
But too much has been going on on the diplomatic front recently for this visit to be wholly "non-political".
It has important symbolism at the very least and it is also a signal of a desire by the British government to continue to engage in what the diplomats call "constructive dialogue".
Good cop, bad cop
The broad picture is that Britain is part of a Western effort to bring about change in Iran.
The British government is in a European troika with the French and Germans playing the "good cops", compared to the more critical approach of the Americans, cast as the "bad cops".
Dr Haleh Avshar, professor of Middle Eastern Studies at York University, placed the visit in this context.
She told the BBC: "I think that the Iranians will welcome such a visit. The important thing for the Iranians is that Britain and Europe are really sending a hand of protection against the kind of labels which America was placing on Iran."
The most recent focus has been Iran's nuclear programme.
Iran was discovered to have been secretly developing a centrifuge for the enrichment of uranium and has now signed an agreement with the UN nuclear agency, the International Atomic Energy Agency, to allow for stricter inspections.
It has also said it is suspending the enrichment procedure for the moment.
As part of the negotiations leading to this agreement, the British, French and German foreign ministers went to Tehran and promised that Europe would supply Iran with the technology needed and, if necessary, the fuel required, to drive Iran's civil power station.
Iran had argued that it could not rely on outside suppliers and that was why it wanted to develop its own fuel enrichment capability.
It may of course continue to do this, which is why the issue remains quite tense.
The United States is suspicious of Iranian intentions and Israel is alarmed.
Political reform
This visit therefore can be seen as a goodwill gesture by the British government, a symbol that Britain is mindful of its new relationship with Iran and wants to build confidence in it.
There is also the question of internal political reform, which is much harder for outsiders to influence.
Currently the parliamentary elections on 20 February are overshadowed by the refusal of the country's religious overseers, the Council of Guardians, to approve some liberal candidates.
Here again the European idea is to get friendly and try to encourage change while the United States emphasizes the remaining problems and offers a dialogue rather than diplomatic relations.
Prince Charles' fascination with Islamic and other ancient history was made use of by the Foreign Office in 1996 when it sent him on a visit to Central Asia and the new countries which broke away from the old Soviet Union - Turkmenistan, Uzbekistan and Kazakhstan.
The prince was never quite at ease on this journey, took his own cook, insisted that his hotel windows open and managed to go nine days without once speaking to the small press party with him.
But he went about the political business of meeting the new leaders.
This included a bizarre visit to the pink desert palace of Turkmen President Niyazov, who showed the prince his prize racehorses and his maidens serving mint tea.
He had his reward in visiting the wonders of the Silk Route and indeed he only seemed to come to life when he was tramping over the ruins of the lost city of Merv and gazing at the wonders of Samarkand. "
It's not often I can say that I envy the Prince of Wales but I do until I can make my own trip to Samarkand.
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