Admit it—you know all the lyrics, you've seen "Mamma Mia!," and you still have Abba albums in your basement. Now see the museum. Opened in May of 2013, it's a kitschy temple to 1970s bad taste. The halls are crammed with gold records, outrageous stage outfits, the mixing table from Polar Studios, even the helicopter from the "Arrival" album cover. Just submit. You know you want to, and resistance is futile anyway. Tip: The museum has a smart policy of letting visitors in at alotted times, so you won't have to wait in lines.