Chris Martin felt that A Head Full of Dreams marked the end of something for Coldplay. In his mind, the band’s lead singer compared it to the seven colors of the color spectrum—on their seventh record, they were completing a journey. It made for a dazzling and joyous album, something that felt like a culmination over everything the four-piece had explored over the previous 15-plus years. There were no concerns about what was cool and what wasn’t anymore. Coldplay were way beyond that, more interested in celebrating that they were a band who loved pop music as much as they loved rock ’n’ roll, so why not combine it all? To that end, A Head Full of Dreams features appearances from Beyoncé, Noel Gallagher, Brian Eno, Tove Lo, and Merry Clayton with some guests that went beyond the realm of musical peers. There’s the political—Barack Obama pops up on two tracks for spoken-word excerpts—and the personal in a Coldplay Jr. choir made up of all their children, plus Martin’s ex-wife Gwyneth Paltrow singing a line referring to their breakup on the tender ballad “Everglow.” Beginning work on the album directly after the completion of Ghost Stories’ low-key introspection, A Head Full of Dreams was designed to be that record’s opposite, a return to big holler-along choruses and monumental, hug-your-mate hooks. Teaming up with megahit specialists and Grammy-winning production duo Stargate, they dived deeper into the pop world than they ever had before. From the spiraling riff that conducts the pulsing dance-pop of “Adventure of a Lifetime” to the euphoric “whoa-oh-oh”s of the title track, this was Coldplay at their most unashamedly positive and uplifting. On the irresistible R&B grooves of “Hymn for the Weekend,” Martin and Beyoncé joined forces for one of the group’s most rousing and rhapsodic choruses. The idea behind A Head Full of Dreams was that if you focus on something hard enough and want it to happen, you can will it into existence. Here, all of Coldplay’s dreams came true. Their first spectrum ended with the biggest of bangs.