Did Marvel ever do hard continuity reboots like DC did over the decades?

I was a big DC nut as a kid starting 35 years ago, and they always seemed obsessed with rebooting cotinutity. Either a hard or soft reset.

Did Marvel ever do the same? I know the Ultimate universe was a parallel one, and I can remember in the 90's there was a John Byrne Spider-man origin reboot which was quickly forgotten after fans hated it. But did Marvel ever have any "Crisis" that refreshed everything?