Katy Perry made her way to Washington DC this week to perform during a concert commemorating the Special Olympics. Afterward, the singer posted a picture of her performance, writing, "What an incredibly beautiful evening being invited to sing at the White House for Potus, Flotus & many special Olympic attendees tonight to celebrate these incredibly inspired men & women. I see them beyond their obstacles. I hope you can join me." This week also brought fun appearances from the British royal family, a stylish moment from Michelle Obama, and more, so catch up with a look at the week's best pictures from across the globe!