Photos of the week: 4/21 - 4/28

This week, President Trump paid a visit to the Walter Reed Military Medical Center in Maryland to bestow a Purple Heart onto Sergeant First Class Alvaro Barrientos, who was injured in Afghanistan. On Friday, the president met with President Mauricio Macri of Argentina at the White House along with their wives.

People around the world commemorated Earth Day on Saturday, which was marked by the March for Science held in several different cities.

The closest-ever photo of Saturn's atmosphere was also released this week as NASA's Cassini spacecraft made its final pass by the planet.

Take a look through the slideshow above to see photos from all of these stories and more, and be sure to check back next week for our selection of the best photography from the coming seven days.