This White House photograph of President Barack Obama at the Dubliner Irish pub in Washington, D.C. was taken by Pete Souza on March 17, 2012. President Obama visited the Dubliner on St. Patrick's Day with his Irish cousin, Henry Healy (center), and Ollie Hayes, a pub owner from Moneygall, Ireland (right).

This White House photograph of President Barack Obama and Vice President Joseph R. Biden outside the Oval Office was taken by Pete Souza on March 17, 2015. President Obama and Vice President Biden are pictured in festive ties walking to the motorcade on the South Grounds of the White House for departure to the U.S. Capitol in Washington, D.C. for a St. Patrick's Day luncheon.

This photograph of President Ronald Reagan was taken by Pete Souza on March 17, 1988. President Reagan is pictured walking back to the Oval Office on the South Grounds in festive attire following a St. Patrick's Day luncheon at the United States Capitol.

This White House photograph of President Barack Obama delivering a toast during a St. Patrick's Day luncheon at the United States Capitol was taken by Pete Souza on March 17, 2015. President Obama is pictured alongside Taoiseach Enda Kenny of Ireland, also known as the prime minister.

This White House photograph of President Barack Obama at the Dubliner, an Irish pub in Washington, D.C., was taken by Pete Souza on March 17, 2012. President Obama is shown greeting the crowds on St. Patrick's Day.

In this photograph by Pete Souza, President Barack Obama has lunch with Speaker of the House Nancy Pelosi and Taoiseach Brian Cowen of Ireland on March 17, 2009. President Obama and Cowen, the prime minister of Ireland, attended a St. Patrick's Day lunch hosted by Speaker Pelosi in the Rayburn House Office Building of the United States Capitol complex.

In this photograph by Pete Souza, President Barack Obama and First Lady Michelle Obama speak with Taoiseach Enda Kenny of Ireland and his wife, Fionnuala Kenny, on March 17, 2011. President and Mrs. Obama welcomed the Kennys in the Green Room of the White House prior to a St. Patrick's Day reception. Kenny was taoiseach, or prime minister, from 2011 to 2017.

This photograph of President Ronald Reagan watching television coverage of the Space Shuttle Challenger explosion was taken by Pete Souza on January 28, 1986. President Reagan, along with members of this West Wing staff, watched the coverage from the Oval Office Study, which is located near the Oval Office in the West Wing. From left to right are: White House Press Secretary Larry Speakes, W. Dennis Thomas, Jim Kuhn, President Reagan, White House Communications Director Patrick J. Buchanan, and Donald T. Regan. The Challenger exploded just 73 seconds after it took off from Cape Canaveral, Florida, killing all seven crew members on board.

This photograph of President Barack Obama delivering a statement on the death of Osama bin Laden was taken by Pete Souza on May 1, 2011. President Obama spoke live on television from the East Room late on May 1. Bin Laden was the leader of the terrorist group al Qaeda, who were responsible for the September 11, 2001 terrorist attacks on the World Trade Center in New York City, the Pentagon in Arlington, Virginia, and Flight 93, which crashed in Shanksville, Pennsylvania. His death was carried out through a military mission led by members of the United States Navy SEALs.

In this photograph, President Barack Obama is interviewed by American journalist Steve Kroft on September 26, 2014. Kroft spoke to President Obama for a segment on the television news magazine, "60 Minutes." The two spoke in the Diplomatic Reception Room of the White House, and occurred ahead of the midterms elections and President Obama's final two years in office.

In this photograph by Pete Souza, President Barack Obama meets with representatives from FIFA (Federal Internationale de Football Association) on July 27, 2009 in the Oval Office. President of FIFA, Joseph S. "Sepp" Blatter, is seated to President Obama's left and presented Obama with jerseys for his two daughters, Malia and Sasha. Obama welcomed Blatter to the White House to discuss the the United States' bid to host the FIFA Men's World Cup in 2018 or 2022, which would ultimately go to Russia and Qatar.

In this photograph by Pete Souza, First Lady Michelle Obama meets soccer superstar David Beckham at a dinner hosted by Mrs. Obama and her husband, President Barack Obama, at Winfield House in London, England on May 25, 2011. Winfield House is the residence of the United States ambassador to the United Kingdom of Great Britain and Northern Ireland. President and Mrs. Obama hosted the dinner in honor of Queen Elizabeth II of Great Britain and Prince Philip, Duke of Edinburgh (pictured next to Mrs. Obama) following a State Banquet hosted by the royal couple at Buckingham Palace the previous evening. The two dinners were a part of President Obama's two day State Visit to the United Kingdom.

In this photograph by Pete Souza, President Barack Obama watches the United States Men's National Soccer team play Ghana in the FIFA Men's World Cup on June 26, 2010. President Obama watched the game from a room at the Intercontinental Hotel in Toronto, Canada during the G20 Summit. The United States played Ghana in the knockout stage, ultimately losing 1-2 to the African nation.

In this photograph by Pete Souza, President Barack Obama tosses a soccer ball after a Rose Garden celebration with the Columbus Crew on July 13, 2009. The Major League Soccer (MLS) team visited with President Obama following their 2008 MLS Cup Championship. Obama tossed the soccer ball in the air on his way back to the Oval Office. The ball, along with team banner and uniform, were gifts for Obama from the team.

In this photograph by Pete Souza, President Barack Obama watches the United States Men's National Soccer team play Belgium in the FIFA Men's World Cup on July 1, 2014. President Obama watched the game with staff in the Eisenhower Executive Office Building's South Court Auditorium. The United States played Belgium in the knockout stage, ultimately losing 1-2 to the European nation.

In this photograph by Pete Souza, President Barack Obama and First Lady Michelle Obama host a lunch for extended members of the Bush family in the Red Room on May 31, 2012. The Bush family visited the White House that day for the unveiling ceremony of President George W. Bush and First Lady Laura Bush's official White House portraits. The ceremony took place in the East Room. Seated clockwise from President Obama are: former First Lady Barbara Bush, Bucky Bush, Doro Bush Koch, Jenna Bush Hager, Marvin Bush, Jody Bush, former President George W. Bush, Mrs. Obama, former President George H. W. Bush, Patty Bush, Bobby Koch, Barbara Pierce Bush, Margaret Bush, Jonathan Bush, and former First Lady Laura Bush.

This photograph is of President Barack Obama and First Lady Michelle Obama, along with Vice President Joe Biden and Second Lady Dr. Jill Biden, descending the Grand Staircase before delivering remarks at a Hanukkah reception in the Entrance Hall of the White House. Pete Souza photographed this moment on December 8, 2011.

In this photograph taken by Pete Souza, President Barack Obama greets members of the DePaul University women's basketball team. The team visited the White House on June 14, 2013 in celebration of their NCAA Division III Women's Basketball Championship. President Obama greeted the group in the Blue Room.

This photograph of President Ronald Reagan with members of Georgetown University men's basketball team was taken by Pete Souza on April 7, 1984. President Reagan welcomed the Hoyas to the Rose Garden following their victory over the University of Houston at the NCAA Division I Men's Championship on April 2. John Thompson, at left, became the first African-American head coach to win the championship. Also captured in this photograph are players Ralph Dalton, Reggie Williams, and Michael Jackson.

In this photograph, President Ronald Reagan poses with coach John Thompson and center Patrick Ewing of the Georgetown University men's basketball team. The trio were shot in the Map Room on the Ground Floor of the White House as part of a photo shoot for the cover of "Sports Illustrated" magazine by Pete Souza on November 11, 1984. The Georgetown Hoyas won the NCCA Division I Men's Championship the previous April. The Hoyas championship was the first for the university and made Thompson the first African-American head coach to lead his team to victory.

In this photograph, President Ronald Reagan participates in a ceremonial wreath laying at the Tomb of the Unknown Soldier in Arlington National Cemetery on Veterans Day 1985. Since 1921, presidents have paid their respects at the Tomb of the Unknown Soldier, often in observance of military commemorations including Veterans Day and Memorial Day.

This photograph was taken by Pete Souza on October 30, 2015, during a Halloween celebration at the White House hosted by President Barack Obama and First Lady Michelle Obama for local children and military families. Here, the president and first lady react with delight to a young trick-or-treater dressed as a pope in a miniature popemobile. The previous month, on September 23, 2015, President Obama had welcomed Pope Francis at the White House. It was the third papal visit to the White House, following the visits of Pope John Paul II in 1979, and Pope Benedict XVI in 2008.

This photograph, taken by Pete Souza on October 31, 2014, shows the South Portico of the White House festively decorated for a Halloween celebration hosted by President Barack Obama and First Lady Michelle Obama for local children and military families. The decorations included large inflatable pumpkins and facades of trees with autumnal leaves.

In this photograph, taken by Pete Souza on October 31, 2009, President Barack Obama, First Lady Michelle Obama, and Marian Robinson, the first lady's mother, wait outside the North Portico to greet trick-or-treaters during a Halloween celebration at the White House. Costumed characters from the "Star Wars" franchise, including Chewbacca and a Stormtrooper, also wait to greet the children. That day, the president and first lady invited local schoolchildren to trick or treat at the White House and also hosted a Halloween reception in the East Room for military families and the children of White House staff.

In this photograph, President Barack Obama and First Lady Michelle Obama return to the White House after joining White House staff on the South Lawn to observe a moment of silence in commemoration of the 14th anniversary of the terrorist attacks against the United States on September 11, 2001. This photograph was taken by White House photographer Pete Souza, from behind a planter on the Truman Balcony. In 2002, President George W. Bush designated September 11th as Patriot Day, a time that has been recognized through presidential proclamations as a national day of remembrance, prayer, and service. Presidents and first ladies typically commemorate the day through moment of silence observations on the White House South Lawn, and by attending remembrance ceremonies at sites affected by the terrorist attacks.