Last month, on Earth Day, the National Zoo and indie band Portugal the Man announced the #EndangeredSong campaign, which aims to raise awareness about the critically endangered Sumatran tiger through a special song. On Monday, May 12, you can hear that song and others for free when the band perform a concert at the zoo’s band shell at Lion/Tiger Hill. The “stripped-down” show starts promptly at 6:30, and while the concert area holds about 1,500 we imagine you’ll want to get there early for a good view. Registration is available through Eventbrite.