Photo by Daniel Knighton for Getty ImagesYes bassist Chris Squire has passed away, according to a Facebook message from the band today. The 67-year-old rock legend had just announced he'd been diagnosed with a rare form of leukemia stepped out of the band's North American tour (the first Yes shows he'd ever miss playing) a month ago. Squire was Yes's only constant member; after founding the band with original lead singer Jon Anderson, Squire would stick through every Yes incarnation from the beginning and play on every studio album.If you're a rock fan worth your snot, you know a little Yes. They started out playing bluesy prog in the late 60s and grew incrementally weirder on The Yes Album, Fragile and Close to the Edge, a string of undeniable classics of the form in the 70s, fading briefly but rising again as a sleek, successful pop rock act on 1983's triple platinum selling 90125 as many of their peers retired, having been declared dinosaurs, or went underground to lick their wounds. Peep archival footage of the band performing Fragile highlight "Roundabout" on the 1972 Close to the Edge tour, with Squire in full caped glory, below.