President Obama's appearance at Nationals Park, the 100th anniversary of the first time a U.S. president threw out the first pitch at a major league baseball game. For other photos of the 2010 Opening Day at Nationals Park, see this gallery.

Coming out on the field.

On the mound.

Getting his gear ready. (Except that it's, ahem, a White Sox cap.)

The pitcher sets.

The windup.

On its way.

The follow-through.

He seems happy with it.

Walking off with his catcher, Ryan Zimmerman.

Working the refs.

I think he's looking right at me!

Greeting some local kids.

Last wave.

Event Galleries:

2013:

03/28/13: Inside Gordon Biersch

01/27/13: 11th Street Bridges Project Progress Photos

2012:

11/16/12: Canal Park Opening Day

11/16/12: Canal Park Opening Day - Speeches and Ice Rink Ribbon Cutting

11/16/12: Canal Park Opening Night

09/14/12: A Trip Around the 11th Street Bridges Project

09/06/12: Boilermaker Shops Interiors

07/30/12: Canal Park Progress Photos from Above and Inside

06/26/12: Inside the Trash Transfer Station: Exteriors

06/26/12: Inside the Trash Transfer Station: Interiors

05/19/12: Changes Along 11th Street SE

04/11/12: Fairgrounds Interior Shots

04/03/12: Fairgrounds Exterior Shots

01/25/12: Foundry Lofts Nearly Finished

01/08/12: Early 2012 11th Street Bridges Project Photos

01/08/12: Random Images From Along and Across the Anacostia River

2011:

12/22/11: Lot 38 Espresso Grand Opening (+1 Day)

11/25/11: Yards/Teague Connector Bridge Sunny Day Reshoot

11/22/11: Yards/Teague Connector Bridge Opening

11/01/11: Foundry Lofts Construction Progress

10/10/11: Progress on the New 11th Street Bridges

10/07/11: New Southbound DC 295 Flyover Bridge

04/30/11: A Few Shots Worth Capturing

04/23/11: Little Updates from the Yards Park

02/15/11: Kick-Off to Renovation of 225 Virginia/200 I

2010:

10/16/10: Early Fall Late Afternoon at the Yards Park

09/24/10: Nighttime at the Yards Park

09/07/10: Yards Park Ribbon Cutting Ceremony

08/31/10: Canal Park Groundbreaking Ceremony

08/27/10: Yards Park Near Completion

05/25/10: Yards Park Construction Progress

04/10/10: An Early Spring Boat Cruise on the Anacostia

03/01/10: Yards Park Construction Photos

02/25/10: Trapeze School Pre-Opening

02/07/10: Blizzard of 2010

2009:

10/11/09: The Chair on the Fence

09/29/09: Assorted River and Ballpark Photos at the End of the Second Season

08/27/09: Diamond Teague Park and Piers

08/26/09: Capitol Quarter Ribbon Cutting

05/29/09: Artomatic 2009 Kickoff

05/28/09: Groundbreaking for the Park at the Yards

2008:

11/15/08: Second Anacostia Waterfront Community Information Fair

10/29/08: Announcement of Public-Private Partnership for the Waterfront Park at The Yards

08/23/08: Anacostia Community Boathouse Youth River Sports Day

03/12/08: Frederick Douglass Bridge Rededication

2007:

10/03/07: Groundbreaking at the Yards

10/22/07: Capitol Riverfront Business Improvement District Kickoff Ceremony

07/06/07: JPI/Capitol Yards Groundbreaking Ceremony

06/26/07: Capitol Quarter Groundbreaking Ceremony

Nationals Park Event Photo Galleries:

2012:

04/12/12: Nationals 2012 Home Opener/Opening Ceremonies

04/12/12: 2012 Nationals Home Opener

03/26/12: The *Other* Nats Park (Spring Training 2012)

03/26/12: Nats vs. Astros at Spring Training

2011:

06/14/11: An Evening at Nats Park

06/13/11: First Look at New Nationals Park Concessions

03/31/11: 2011 Opening Day at Nationals Park

03/30/11: 2011 NatsFest

2010:

12/11/10: New Baseball Art on Stadium Garages

09/23/10: A Stan Kasten Photo Gallery

04/05/10: President Obama Throws Out the First Pitch at Nationals Park

04/05/10: Opening Day 2010 at Nationals Park

03/31/10: Pre-Opening Day Ballpark Media Tour

2009:

09/29/09: Assorted River and Ballpark Photos at the End of the Second Season

07/09/09: Preparations for Elton John and Billy Joel

05/15/09: Opening Night at the Bullpen Beer Garden

04/13/09: 2009 Opening Day at Nationals Park

04/03/09: What's New at Nationals Park 2009

02/13/09: Diamond Teague Park Groundbreaking

01/25/09: 2009 NatsFest

2008:

06/05/08: Nighttime at Nationals Park (Outside and Inside)

05/06/08: A Visit to the Nationals Park Infield

05/04/08: Nationals Park in Early May (Including Kids Running the Bases)

Scenes from the Inaugural Season at Nationals Park

04/12/08: Washington Nationals Dream Foundation Neighborhood Initiative Announcement

03/30/08: Opening Night at Nationals Park - Before the Game

03/29/08: First Major League Exhibition Game at Nationals Park--Part Three (Around the Ballpark)

03/29/08: First Major League Exhibition Game at Nationals Park--Part Two (Pre-Game Ceremonies)

03/29/08: First Major League Exhibition Game at Nationals Park--Part One (Arrival/Batting Practice)

03/28/08: First Batting Practice at Nationals Park

03/27/08: Nationals First Visit to Completed Nationals Park

03/27/08: Media Tour--Strike Zone and Concession Photos

03/27/08: Media Tour--Interior Photos

03/22/08: First Ballgame at Nationals Park (GW vs. St. Joseph's) - Part Two

03/22/08: First Ballgame at Nationals Park (GW vs. St. Joseph's) - Part One

03/19/08: Nighttime Visit to the Ballpark

03/19/08: Stan Kasten Rides the Metro to Nationals Park

03/06/08: Nationals Ballpark Cherry Blossom Tree Planting

03/04/08: Nationals Ballpark Home Plate Installation and Video Board Unveiling

2007:

11/13/07: Nationals Ballpark Construction Media Tour - Unveiling of the Turf

09/01/07: A Visit to Nationals Park

07/11/07: Nationals Ballpark Topping Out

03/26/07: Nationals Ballpark Construction Media Tour

2006:

10/11/06: Nationals Ballpark Construction Media Tour

05/04/06: Nationals Ballpark Ceremonial Groundbreaking