HARI SREENIVASAN: President and Mrs. Obama began a full state visit to Britain today. It was only the second ever accorded to a sitting American president.
Day one was filled with pomp and ceremony, starting with the presidential motorcade's arrival at Buckingham Palace and a greeting by Queen Elizabeth and her husband, Prince Philip. The Obamas were given a private tour, including a look at historical pieces from the queen's private gallery. One was a photograph of the HMS Resolute, a lost British ship found in the 1850s by the U.S. Some of its timbers were used in the desk that sits in the Oval Office at the White House.
Separately, the Obamas met for 10 minutes with newlyweds Prince William and Kate Middleton, now known as the duke and duchess of Cambridge. The president also spoke with choirboys at Westminster Abbey and laid a wreath at the Grave of Britain's Unknown Warrior.
From there, it was on to 10 Downing Street for a photo-op with Prime Minister David Cameron and his wife. The two leaders hold formal talks tomorrow, and the president addresses Parliament there as well.
For today, though, the two leaders did manage one break in the formality, playing ping-pong with students at a London school.
In Afghanistan, 10 workers were killed when a roadside bomb ripped through their vehicle in the south. They were being driven to work to clean rivers and streams in the Panjwaii district of Kandahar Province. Another 28 people were wounded. The region has seen a rise in incidents recently, since the Taliban launched a spring offensive.
Egypt's former President Hosni Mubarak will stand trial on charges he conspired in the shooting of protesters. More than 800 people were killed during the uprising against his rule this year. The country's prosecutor-general announced plans for the trial today. The 83-year-old Mubarak, his two sons and a close friend were also charged with abusing their power to amass wealth.
An ash cloud from an erupting volcano in Iceland forced airlines to cancel roughly 500 flights today in Britain and Scandinavia. And part of Germany's airspace was closing tomorrow. But the worst effects were in Iceland itself.
We have a report from Tom Clarke of Independent Television News.
TOM CLARKE: Driving towards the Grimsvotn volcano, you can watch the ash get thicker.
Yesterday, the cloud was so dense, this road was impassable, but high winds have temporarily lifted the pall. Combine this dust with the gale, and Iceland's unearthly landscape looks even more like the surface of the moon. And it's about as deserted. People have left or are staying indoors. But these rescuers have plenty of other lives to save.
It's hard to persuade hearty Icelandic sheep indoors, but they need to get them in soon. People here can protect themselves with goggles and face masks against the abrasive ash, but it's quickly blinding these lambs, their eyes already grit-filled and streaming.
THORUNN EDDA SVEINSDOTTIR, farmer's wife (through translator): I don't think much about people having trouble going on holiday or if there is a bit of ash falling here, there, or wherever. They should come and take a look at what's going on at my farm.
TOM CLARKE: This is Iceland's most powerful eruption since 1947. It's estimated that, yesterday, Grimsvotn was spewing out 10,000 tons of ash into the sky every second.
Even though we're about 30 miles still from the Grimsvotn volcano, the air and ground here is thick with volcanic ash. But even though this is Iceland's biggest volcanic eruption for 60 years, some researchers think it might not be as disruptive as the last one. And it's because of this volcanic ash. It's heavier and, therefore, simply might not spread quite as far.
And while the initial eruption was massive, it has now weakened considerably. Further good news for Europe's air travelers is that strong, but changeable winds should help disperse the ash cloud in no particular direction. Much of Grimsvotn's ash has already landed here, choking the air intakes of cars, piling in drifts outside the supermarket. It's even turning white swans' plumage gray. So far, it looks like Iceland is bearing the brunt of this eruption.
HARI SREENIVASAN: Last year's eruption of a different volcano in Iceland led to widespread flight cancellations across Europe. It cost the industry $1.7 billion.
Vice President Biden convened congressional negotiators for the latest round of budget talks today. There was no sign of agreement on a spending plan for the coming year or on a deal to raise the nation's debt ceiling. Republicans have demanded major spending cuts as the price for increasing the debt ceiling. If there is no agreement, the government could default by early August.
The main opposition party in Greece has rejected the prime minister's call for more spending cuts to control the country's spiraling debt. The news today raised new concerns about Europe's financial stability. And that, in turn, undercut any momentum on Wall Street. The Dow Jones industrial average lost 25 points to close at 12,356. The Nasdaq fell more than 12 points to close at 2,746.
The National Transportation Safety Board has found no definitive cause for the plane crash that killed former Sen. Ted Stevens of Alaska and four others last year. The report today said the pilot was temporarily unresponsive before the small plane went down near Dillingham, Alaska. It also said a warning system which could have told him he was approaching a mountain had been inhibited. There were no indications of mechanical problems, and toxicology reports ruled out drugs, though the pilot and his family had a history of strokes.
It was impossible to know more because there was no flight data or cockpit voice recorder on board.
Those are some of the day's major stories.