Biko, released on Peter Gabriel's third eponymous album in 1980, was for a rather long time his anthem. It's a tribute to Stephen Biko, a South African black civil rights activist who was arrested, tortured, and killed by the police in 1977. You can read about the man at his own node while I talk about the song.
Biko begins with a syncopated drum beat that carries throughout the entire song. The very distorted guitar of David Rhodes precedes the entry of Gabriel's vocal by a beat, and the funeral march progresses the same from there, except for the brief synthesized bagpipe solos between verses. It's a meditative song, which certainly wouldn't be very good without its meaning.
Obviously, it strikes a chord with his audience.
In concert, this song usually comes last or as an encore. At the very end, in the official recorded versions you'll find, the song fades out as the drums continue and all the musicians chant in unison. Well, in person, that just doesn't happen.
The version of Biko in Gabriel's PoV video shows a beaten and sweaty PG, after crowdsurfing during Lay Your Hands On Me, dancing around like an ape in Shock the Monkey, and dancing around like a less hairy ape for In Your Eyes, finally leaves the stage in exhaustion, along with Youssou N'Dour and company. The band stays for another good 10 minutes while the audience sings along, pumping their fists in the air. Around 10,000 people raising their fists together is a pretty amazing sight, even on video. The one bootleg I've heard is around 15 minutes long, and at its close even the drums have stopped.
This song has been played at every Peter Gabriel concert since 1980, up to and including Woodstock 1993. You can listen to live versions on Peter Gabriel Plays Live (1983), the PoV video (1990), and the Woodstock 1993 compilation.