President Obama boards Air Force One June 2, 2009 as he starts a 4-day trip, which will take him to Saudi Arabia, Egypt, Germany and France.

Here are the big stories on the agenda today:

• President Obama is heading to the Middle East.  He's expected to touch down in Saudi Arabia this morning, with the goal of “resetting” relations with the Muslim world.  We are live in Riyadh and previewing the president’s highly anticipated speech tomorrow from Cairo.
• Signs of debris, but no survivors from the Air France plane that crashed in the Atlantic off the Brazilian coast.  The U.S. Navy is joining Brazil and France in the search for wreckage – and answers.  One expert saying it could be among the hardest recoveries since the search to find the titanic, which took decades!  Investigators say the so-called “black boxes” probably survived, but they are not hopeful they will find them.
• A CNN Special Investigation.  Every day, desperate Americans are flying to places like Peru, Mexico and China, seeking a miracle in the form of stem cell therapy.  Many of them – parents with children who are sick, or dying.  They're spending tens of thousands of dollars – despite the fact there's no scientific evidence it works.  Drew Griffin talks to doctors, looks for answers and speaks to families that are literally putting everything on the line for an experiment.