Presidential candidate Senator Amy Klobuchar (D-MN) at a rally in Falls Church, VA. (David Fisher/For personal)

With the sun beating down, Tyler Bowser services a rain gage. David Fisher/USGS

The Amphitheater at Arlington Memorial Cemetery, Memorial Day 2023.

Attendees at an Amy Klobuchar rally wear “Amy for America” stickers. (David Fisher/For personal)

Eric Boyd cross the bridge to the control tower at Jennings Randolph Lake. David Fisher/USGS

A supporter of Andrew Yang holds a sign. (David Fisher/For personal)

Supporters wave “Amy for America” signs at a rally. (David Fisher/For personal)

Presidential candidate Andrew Yang speaks at a campaign rally at the Lincoln Memorial. (David Fisher/For personal)

German Minister for Economic Affairs and Energy Peter Altmaier speaks with media outside the White House following a meeting on tariffs with U.S. Secretary of Commerce Wilbur Ross. (David Fisher/For personal)

Tony Tallman and crew set up air pressure sensors in a forest at Nassawango Creek. David Fisher/USGS

A Washington Capitals fan passionately yells while at the teams’ Stanley Cup Championship parade. (David Fisher/DC Refined)

Eric Boyd pulls an ADCP across North Branch Potomac River. David Fisher/USGS

Nick Giro services a USGS gage at Wheel Creek. David Fisher/USGS

Tomb of the Unknown Soldier, Memorial Day 2023.

Soldiers guard the Tomb of the Unknown Soldier on Memorial Day. (David Fisher/For personal)

Klobuchar speaks to a Falls Church audience in front of the Seal of Viriginia. (David Fisher/For personal)

Jacob Mavrogeorge carries equipment at Nassawango Creek. David Fisher/USGS

Heavy rains caused flooding in Rock Creek Park, forcing the road to be closed. (David Fisher/For personal)

A woman looks on at the Memorial Day 2018 Parade.

Two soldiers participate in the Changing of the Guard on Memorial Day at Arlington National Cemetery. (David Fisher/For personal)

Picking vegetables on a rooftop garden in downtown DC. David Fisher/DC Refined

After a successful day servicing a USGS gage, technicians leave Ship John Shoal in the distance. David Fisher/USGS

Amy Klobuchar pauses during a campaign rally in Virginia in 2020.

Senator Bernie Sanders (D-VT) greets supporters after speaking at a rally for Democratic gubernatorial candidate Ben Jealous. (David Fisher/For personal)

President Donald J. Trump assists a soldier in laying the wreath at the Tomb of the Unknown Soldier on Memorial Day 2018. (David Fisher/For personal)

A worker harvests at Up Top Acres, a rooftop farm in Downtown D.C. (David Fisher/DC Refined)

The sensor equipment at Ship John Shoal needs to be cleaned regularly to prevent fouling. The site is covered in bird droppings, a result of the lighthouse being the only solid ground for miles around. David Fisher/USGS

Michael Brownley steers a boat through a particularly foggy Delaware Bay. David Fisher/USGS

Presidential candidate Andrew Yang greets supporters during a rally at the Lincoln Memorial on April 15, 2019. (David Fisher/For personal)

Rep. Joaquin Castro (D-TX) speaks to the media after Congress voted to stop President Trump’s emergency declaration to secure funds to build a border wall. (David Fisher/For personal)

Natalie Hall looks on after installing a camera to monitor Ten Mile Creek. David Fisher/USGS

Andrew Yang at a rally at the Lincoln Memorial.

Ashley Ryan and Nick Giro paddle the Anacostia River to collect data on the river. David Fisher/USGS

Brooklyn Sandwich Co. is a food truck in downtown D.C., or as manager, Aharon Levy puts it, “An upscale deli on wheels.” (David Fisher/DC Refined)

Secret Service patrol the Amphitheater at Arlington Memorial Cemetery on Memorial Day 2018.

Sen. Chris Murphy (D-CT) speaks while Sen. Richard Blumenthal (D-CT) looks on.

Former Vice President Al Gore speaks to students and faculty about climate change at the University of Maryland. (David Fisher/UMD Mitzpeh)

The Bethesda Trolley Trail bridges over the I-495 Beltway. It's a great spot to observe the road. (David Fisher/DC Refined)

Leah Staub collects sediment from a creek along the Eastern Shore of Maryland. David Fisher/USGS

After a successful day servicing a USGS gage, technicians leave Ship John Shoal in the distance. David Fisher/USGS

Tony Tallman sets up an air pressure sensor. David Fisher/USGS

Spectators use their phones to capture Mike Pence sworn in as Vice President. (David Fisher/For personal)

David Fisher/USGS

A crowd watches as a helicopter takes off, carrying with it a loop that will scan the surface for data on groundwater in the Delaware Bay area. David Fisher/USGS

Senator Bernie Sanders (D-VT) endorses Ben Jealous for Maryland governor. (David Fisher/For personal)