Suggestion: A way to see content from all communities

I joined a couple communities and noticed my home page feed changed pretty drastically. Where before I think I was seeing content from a default set of communities, now I'm only seeing content from the communities I joined. That's fine, actually. But there should be an easy way to flip to content from all communities. A way to get the pulse of what's going on with the whole site. Or maybe this already exists and I just can't find it?