Today in Pictures: May 4

A helicopter battles a wildfire in Fort McMurray, Alberta, Canada on Wednesday.

Photos: Entire City Flees Raging Wildfire in Canada

President Obama drinks a glass of filtered water from Flint, Mich., on his first trip to the beleaguered city since it became the center of a political and environmental firestorm. Twice during his visit to Flint, Obama took symbolic sips from a glass of Flint tap water.

Faces of Flint: Portraits From the Crisis

A trout splashes into Jamaica Pond in Boston during the annual stocking of the pond.

A model displays a large diamond the size of tennis ball at Sotheby's in New York. The gem's name is "Lesedi la Rona."

The diamond - the largest discovered in over a century - could sell for more than $70 million, auctioneer Sotheby's said.

Farmers work in a field of blossoming tulips in Den Helder, northern Netherlands.

Horses await baths after an early morning workout at Churchill Downs in Louisville, Ky. The 142nd running of the Kentucky Derby is scheduled for Saturday, May 7.

A Kurdish Peshmerga fighter searches a house for ISIS militants in Tel Asqof, northern Iraq, on May 4.

A U.S. Navy SEAL, advising and assisting Kurdish Peshmerga forces, was killed in an ISIS attack in northern Iraq on May 3.

Fans bring their dogs onto the field during the season's first "Bark in the Park" before a game between the San Francisco Giants and the Cincinnati Reds at the Great American Ball Park on May 3 in Cincinnati.

Flames rise in an industrial area south of Fort McMurray, Alberta, Canada, on May 3.