A museum devoted to the pop superstars that were ABBA opened this week celebrating the band’s long list of hits. But it also shows off paraphernalia, including the helicopter featured on the cover of its “Arrival” album, a star-shaped guitar and glitzy costumes the Swedish band wore at the height of its 1970s fame.

Some gear is not on show. With a smirk, band member Bjorn Ulvaeus says certain items are “mysteriously ... forever lost,” conceding that among them are “embarrassing” tight costumes he wore when he was “slightly overweight.”

Some 40 sets of the trademark platform boots and knitted hats are on display in the museum. But visitors can also see digital images of what they would look like in costumes, record music videos and sing such hits as “Dancing Queen” and “Mamma Mia” on a stage next to hologram images of the band members. A telephone also has been placed in a corner and ABBA members have promised to “Ring, Ring” and speak to visitors occasionally.

But the museum also shows a more everyday side of the history of a band that has sold 400 million records and consistently topped the charts in the decade after winning the 1974 Eurovision Song Contest with “Waterloo.”

The band — Ulvaeus, Anni-Frid Lyngstad, Benny Andersson and Agnetha Faltskog — started out as two married couples, and continued performing after their divorces, drifting apart in the early ’80s.

Visitors can listen to the band members’ recollections and one section is dedicated to the breakup and divorces.

“It (touches) on those things as well because we think they are important in telling the story,” Ulvaeus said.

The museum also includes a Swedish Music Hall of Fame, detailing other artists.

Outside the newly built wooden museum, scores of international ABBA fans gathered Monday, singing the band’s songs and hoping to get a glimpse of their idols arriving for a gala dinner.