
President Barack Obama, visiting Watertown, South Dakota, on Friday, May 8, shows off a note given to him by 11-year-old Rebecca Kelley. Rebecca had written him a letter asking him to visit South Dakota, which is the 50th state Obama has visited during his time in office. White House photographer Pete Souza highlights a picture from each state.

Marching at the 50th anniversary of Bloody Sunday in Selma, Alabama, on March 7, 2015.

Air Force One refueling at Elmendorf Air Force Base near Anchorage, Alaska, on November 12, 2009.

Viewing the Grand Canyon in Arizona on August 16, 2009.

Touring tornado damage in Vilonia, Arkansas, on May 7, 2014.

Viewing the Golden Gate Bridge in San Francisco, California, on July 23, 2014.

Playing pool with Gov. John Hickenlooper in Denver, Colorado, on July 8, 2014.

Making last-minute edits to his speech in Newtown, Connecticut, before a vigil for those killed at Sandy Hook Elementary School on December 16, 2012.

Honoring fallen soldiers from Afghanistan at Dover Air Force Base in Delaware on October 29, 2009.

Keeping his distance from a baby alligator on Earth Day at Everglades National Park in Florida on April 22, 2015.

Graduates cheering the President during a heavy downpour at Morehouse College in Atlanta, Georgia, on May 19, 2013.

Swimming at Pyramid Rock Beach in Kaneohe Bay, Oahu, Hawaii, on January 1, 2012.

Posing for a photo with kids at Boise Airport in Idaho on January 21, 2015.

Viewing Chicago, Illinois, at sunset from Marine One on January 11, 2012.

Dropping by the Gingerbread House Bakery in Kokomo, Indiana, with Vice President Joe Biden on November 23, 2010.

Speaking at a grassroots campaign event at Living History Farms in Urbandale, Iowa, on September 1, 2012.

Waving to people after his economic speech in Osawatomie, Kansas, on December 6, 2011.

Greeting troops with Vice President Joe Biden at Fort Campbell in Kentucky on May 6, 2011.

Flying over the Gulf of Mexico from Grand Isle to New Orleans, Louisiana, after the BP oil spill on June 4, 2010.

Hiking with the family on Cadillac Mountain at Acadia National Park in Maine on July 16, 2010.

Graduates celebrating at the U.S. Naval Academy in Annapolis, Maryland, on May 22, 2009.

Discussing the situation in Ferguson, Missouri, while on vacation in Martha's Vineyard, Massachusetts, on August 14, 2014.

Sitting on the famed Rosa Parks bus at the Henry Ford Museum in Dearborn, Michigan, on April 18, 2012.

Talking with letter writer Rebekah Erler at Matt's Bar in Minneapolis, Minnesota, on June 26, 2014.

Meeting on the BP oil spill in the Gulf of Mexico at the Gulfport Coast Guard Station in Mississippi on June 14, 2010.

Consoling families affected by the deadly tornadoes in Joplin, Missouri, on May 29, 2011.

Fly fishing near Bozeman, Montana, on August 14, 2009.

Greeting military personnel at Offutt Air Force Base near Omaha, Nebraska, on August 13, 2012.

Viewing the Hoover Dam in Nevada on October 2, 2012.

Joking with Vice President Joe Biden before a campaign rally in Portsmouth, New Hampshire, on September 7, 2012.

Highlighting the opening of the Point Pleasant Beach boardwalk on May 28, 2013, with New Jersey Gov. Chris Christie and his family after Superstorm Sandy's devastation the previous September.

Having lemonade with Andy and Etta Cavalier at their home in Albuquerque, New Mexico, on September 28, 2010.

Greeting families with former first lady Laura Bush (from left), former President George W. Bush and first lady Michelle Obama before a commemoration ceremony on the 10th anniversary of the 9/11 terrorist attacks in New York on September 11, 2011.

Listening to the President's remarks in Millers Creek, in the foothills of the Appalachians in North Carolina, on October 17, 2011.

Greeting a young boy during a Flag Day celebration on June 13, 2014, at the Standing Rock Sioux Tribe Reservation in Cannon Ball, North Dakota. Cannon Ball is south of Bismarck.

Greeting workers during a shift change at V&M Star, a manufacturer of steel products, in Youngstown, Ohio, on May 18, 2010.

Hugging Amy Simpson, principal of Plaza Towers Elementary School, while viewing the remains of the school after a tornado in Moore, Oklahoma, on May 26, 2013.

Reacting to a quip from a patron at the Gateway Breakfast House in Portland, Oregon, on July 24, 2012.

Addressing a rally in Philadelphia, Pennsylvania, on October 10, 2010.

Viewing the ocean at Brenton Point in Newport, Rhode Island, on August 29, 2014.

Reacting to an enthusiastic greeter at Columbia Metropolitan Airport in South Carolina on March 6, 2015.

Shaking hands with Booker T. Washington students before their commencement ceremony in Memphis, Tennessee, on May 16, 2011.

Trying on a pair of cowboy boots at the University of Texas in Austin on August 9, 2010.

Viewing solar panels at Hill Air Force Base, north of Salt Lake City, in Utah on April 3, 2015.

Greeting the crowd in Burlington, Vermont, on March 30, 2012.

Speaking during a rainstorm in Glen Allen, Virginia, on July 14, 2012. Glen Allen is near Richmond.

Departing Seattle, Washington, on a foggy morning on November 25, 2013.

Celebrating the life of Sen. Robert C. Byrd with Vice President Joe Biden and former President Bill Clinton, at a memorial service in Charleston, West Virginia, on June 28, 2010.

Cheering with the La Follette Lancers football team during their practice in Madison, Wisconsin, on September 28, 2010.

Watching geysers with the family at Yellowstone National Park in Wyoming on August 15, 2009.