A look at key events during the first 100 days of Barack Obama's presidency:
Jan. 22: Obama orders the closure of Guantanamo Bay prison within a year and declares that the United States will not engage in torture.
Jan 23: Obama lifts ban on federal funding for international organizations that perform or provide information on abortions.
Jan. 27: Obama gives first formal television interview as president to Arab television station, telling Muslims, "Americans are not your enemy."
Jan. 29: Obama signs first bill into law, the Lilly Ledbetter Fair Pay Act, making it easier for workers to sue for pay discrimination.
Feb. 3: Former Senate Majority Leader Tom Daschle, D-S.D., withdraws as Obama's nominee for secretary of health and human services.
Special: Obama world's new hope
Feb. 9: Obama holds first prime-time news conference, urging Congress to enact his economic stimulus plan.
Feb. 12: Sen. Judd Gregg, R-N.H., withdraws as Obama's nominee for secretary of commerce.
Feb. 13: Congress completes action on a $787 billion economic stimulus package of tax cuts and new spending, intended to jolt the country out of the worst recession in 50 years.
Feb. 17: Obama signs the stimulus measure into law.
Feb. 19: Obama makes his first visit to a foreign country as president, meeting with Canadian Prime Minister Stephen Harper during a seven-hour visit to Ottawa.
Feb. 22: Obama hosts governors in his first formal dinner at the White House.
Feb. 23: Obama holds a fiscal responsibility summit at the White House, signaling his intention to tackle health care, the budget and Social Security.
Feb. 24: Obama addresses a joint session of Congress for the first time, focusing on economic issues.
Feb. 26: Obama unveils a $3.6 trillion federal budget for 2010 and estimates the federal deficit for 2009 will balloon to $1.75 trillion.
Feb. 27: Obama announces withdrawal of all American combat forces from Iraq by August 2010, but says the U.S. will leave tens of thousands of support troops behind.
March 5: Obama hosts daylong White House summit on health care.
March 9: Obama reverses President George W. Bush's ban on federally funded embryonic stem cell research, and declares that all federal scientific research will be walled off from political influences.
March 11: Obama signs a $410 billion spending bill to keep the government running for the rest of the 2009 budget year. He calls the measure "imperfect" because it includes money for special projects set aside by members of Congress, a practice he pledged to end during the 2008 campaign.
March 16: Obama declares he will stop insurer American International Group Inc. from paying millions in executive bonuses after receiving billions in federal bailout funds.
March 19: Obama becomes the first sitting president to appear on the "Tonight" show.
March 20: Obama releases video message to people of Iran in celebration of Nowruz, the Persian new year and the first day of spring.
March 26: Obama holds "Open for Questions", the first virtual town hall meeting at the White House.
March 27: Obama announces comprehensive new strategy for Afghanistan and Pakistan, including the deployment of 4,000 more military trainers to Afghanistan.
March 30: Obama asserts unprecedented government control over the auto industry, rejecting turnaround plans by General Motors Corp. and Chrysler LLC, and engineering the ouster of GM's chief executive, Rick Wagoner.
March 31: Obama travels to London, the first stop on an eight-day, six country tour of Europe and the Middle East.
April 1: Obama meets with Russian President Dmitry Medvedev and announces start of negotiations on new strategic arms-control treaty.
April 1: Obama and first lady Michelle Obama have a private audience with Queen Elizabeth at Buckingham Palace.
April 2: Obama attends the Group of 20 economic summit in London, where leaders agree to bail out developing countries, stimulate world trade and regulate financial firms more stringently.
April 3: Obama speaks and takes questions from crowd of mostly French and German citizens at a Town Hall meeting in Strasbourg, France.
April 4: Obama attends NATO summit in Strasbourg and gets commitment from allies to send up to 5,000 more military trainers and police to Afghanistan.
April 5: Obama launches an effort to rid the world of nuclear weapons, calling them, during a speech in Prague, "the most dangerous legacy of the Cold War."
April 6: Obama speaks to Turkey's parliament, declaring that "the United States is not, and will never be, at war with Islam."
April 7: Obama pays a surprise visit to Iraq, meeting with U.S. troops and Iraqi leaders.
April 9: Obama sends a request to Congress for $83.4 billion for military and diplomatic operations in Iraq and Afghanistan.
April 10: Obama says the economy is showing "glimmers of hope" after meeting with top economic officials.
April 12: Obama authorizes a military rescue of an American sea captain taken hostage by pirates in the waters off Somalia. The rescue results in the deaths of three pirates and the capture of the fourth, and frees Capt. Richard Phillips.
April 13: The administration announces that Cuban-Americans will be permitted to make unlimited transfers of money and visits to relatives in Cuba. The decision also clears away most regulations that had stopped American companies from bringing high-tech services and information to Cuba.
April 14: The Obamas introduce their new puppy, Bo, in a photo session on the White House lawn.
April 16: Obama meets with Mexican President Felipe Calderon on his first trip to Mexico and Latin America. The leaders agree to cooperate on combating drug violence along the U.S.-Mexican border.
April 17: Obama releases memos from Bush administration authorizing harsh interrogation techniques but says no CIA employees who followed the memos will be prosecuted.
April 17: Obama travels to Trinidad and Tobago for the 34-nation Summit of the Americas and declares that he "seeks a new beginning with Cuba."
April 18: At the summit, Obama shakes hands with Venezuela's Hugo Chavez, the leftist, anti-American leader who had called Bush a devil.
April 19: Obama calls on Cuba to release political prisoners as a way to improve relations with the U.S.
April 20: Obama holds the first formal Cabinet meeting of his administration, ordering department heads to slice spending by $100 million, a tiny fraction of the $3.6 trillion federal budget he proposed a month earlier.
April 21: Obama leaves the door open for prosecution of federal lawyers who wrote harsh interrogation memos during Bush administration and says if there's an investigation, it should be done by an independent commission.
April 22: Obama makes his first visit as president to Iowa, the state where his 2008 Democratic caucus victory launched him toward the presidency.
April 23: Obama tells congressional leaders he will not support creation of an independent commission to investigate the Bush administration's harsh interrogation techniques.
April 24: Obama declines to brand the early 20th century massacre of an estimated 1.5 million Armenians in Turkey a "genocide," breaking a campaign promise.
April 27: Obama says the government is concerned about the spreading swine flu virus but there's not yet "a cause for alarm."