Alan Gilbert has chosen to celebrate the close of his tenure as music director of the New York Philharmonic on a political note, with a program called “A Concert for Unity.” BY inviting musicians from countries including Iran and Israel to join Philharmonic members on the stage on Thursday-Saturday, Mr. Gilbert is clearly trying to steer against the divisive winds coming out of Washington. But he is also interesting himself into a tradition of bridge-building musical events that reach back to the aftermath of World War II. Here are five memorable moments of musical diplomacy: 

Zionsville Community High School has received a plaque of appreciation from the U.S. Dept. of State for hosting three students from Kosovo and Liberia through the YES program during the 2016-17 school year. The YES program offers a competitive grant to students from countries with a significant Muslim population. [...] “The focus of these programs is to encourage diplomacy for future generations in hope of fostering a more peaceful world,” said Jan Ellis, local coordinator. Diella Ymeraga, 17, a Kosovo exchange student, described ZCHS as a good and open-minded community. 

For a few hours on Sunday, Ariana Grande, a 23-year-old pop star from Boca Raton, Florida, was the leader of the free world. The position has been open for months. Contestants ranging from German Chancellor Angela Merkel to, improbably, Chinese President Xi Jinping have been auditioning for the job. [...] While President Trump gutter-tweeted argle-bargle and played another round of golf, Grande delivered what will likely stand as the official American response to the bombing in Manchester and to another terrorist attack, the night before the concert, in London.